Finding excellent free software for your Mac is increasingly tough. In our fourth annual Lifehacker Pack for Mac, we're highlighting the best free downloads for better productivity, communication, media management, and more.
NOTE: This post is outdated. Check out the most recent Lifehacker Pack for a more up-to-date list of essential Mac apps.
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Productivity
Quicksilver
Simply put, Quicksilver makes everything you do on your Mac easier. At its simplest, Quicksilver is a keyboard app launcher. Once you get into it you can use it for quickly writing emails, controlling iTunes, and even browsing your file system. It takes a little bit of effort to get used to it, but it's well worth it, and our beginner's guide will help you along the way. If you want to get a better idea of what it does, check out our video demonstrations. If you're looking for a feature-rich alternative, check out Alfred, and if you want nothing more than a simple app-launcher, pick up Chuck.
Notational Velocity
What makes Notational Velocity great is that it has the exact amount of features needed in a note taking app with no fluff. It does what it needs to: syncs notes across Simplenote or Dropbox (and all apps that support Dropbox), provides a simple place to type notes with basic text options, and allows you to control the app from the keyboard. Notational Velocity has some contenders, including the Simplenote syncing app Metanota, and the much-loved Evernote, but Notational Velocity wins with its mix of features and simplicity.
DashExpander
Text expansion is one those pieces of productivity software that most people only associate with power users, but it's incredibly handy for just about everyone. DashExpander is the only free text expansion software we've found that we really like. The newest version adds an annoying in-app purchase for certain text snippets, but it's still worth checking out for a trial run. It doesn't have the features of the paid apps, but for the standard user it's good to have around.
Wunderlist
You have a nearly infinite amount of choices for a to-do app on your Mac, but Wunderlist is one of our favorites because it's free, syncs to the cloud, and it's cross-platform across just about every modern device. Wunderlist is easy to use and anyone can start making to-do lists right away. Wunderlist isn't packed with as many features as something like OmniFocus, but it's considerably easier to use.
Internet/Communication
Chrome
Everyone has their reasons for loving one browser or another, but on Mac we prefer Chrome over Firefox. It's fast, functional, and syncs everything across your computers (and iOS devices with Chrome mobile). Both Chrome and Firefox are good browsing tools, but if you want to sync up across iOS devices Chrome is your best option.
Sparrow Lite
Sparrow was great when it was essentially a Gmail-only desktop client. Now, it supports all types of email accounts, and works with every major service out there, including your own. Sparrow does everything the default Mail app does, but adds support for labels, filters, and a great interface. The full version gets rid of ads and costs $10, but the lite version is fine for most people and offers a glimpse at what you might be missing.
Adium
Adium doesn't have a lot of complicated features and that's part of the reason we like it. Adium does instant messaging, and it does it well. It supports every major IM client out there, and you can customize it with all sorts of plugins. Apple is releasing a big update to Messages in Mountain Lion that might challenge Adium, but for now, Adium is our favorite IM client.
Skype
Skype is the easiest and most reliable way to video chat on your Mac. As a video chat app it's easy to use and exists on just about every platform imaginable so you can chat with anyone, anywhere. It's far from perfect, but the Mac version has seen stability improvements over the last year. If you're not a fan of Skype or just don't want the extra software, Google+ Hangouts is a fantastic, web-based alternative.
NetNewsWire
Despite the rise of social reader apps, RSS is still the best way to get news from your favorite blogs and papers. Mac's have a lot of options for RSS readers, but NewNewsWire is still the best free app. It syncs directly with Google Reader and has an iPhone version as well. If design is more your thing, Reeder is a great looking alternative that still has solid support, but costs $4.99.
Music, Photos, and Video
VLC
If you want to play videos on your Mac you need VLC. Sure, you could play around with Quicktime codecs for hours, but VLC works right away. If you want to dig into it, VLC also has features like video conversion, but for the average user it's a good video player to have around. If VLC isn't your thing, we suggest checking out Movist.
Handbrake
Handbrake is good at two things: ripping DVDs and converting media files. It's not the most intuitive software in the world, but we've put together a guide to help you get used to it. Once you do, you can convert videos to any format for streaming or even storage on your iPhone. You'll need a copy of the above mentioned VLC to do conversions. If you run into anything Handbrake can't handle Adapter is another piece of free software that should be able to take care of converting everything else.
StreamToMe
If you want to turn your Mac into a movie streaming device, StreamToMe is your simplest option. You can serve up video to your iPhone, iPad, or other computer. It's not particularly hard to use, but we have a video guide if you need a little help. StreamToMe doesn't have the power to stream to Apple TV or any set top box, but for computer-to-computer streaming it does the job
Picasa
Picasa is hands-down the easiest to use free photo management app for Mac. Picasa works both offline and online, and syncs up to Google+ for unlimited backup (at a lower resolution). As a management app it gets the job done and you can organize your pictures in the same way as Apple's iPhoto. If you're looking for something with more features, our pick is Lyn, but you'll have to cough up $20.
Spotify
Love it or hate, every Mac comes bundled with iTunes and you won't find any powerful alternative for cheap. Instead of managing what you own, we'd recommend a streaming service as a replacement. Spotify is our pick, but Rdio is similar and has most of the same music. If you prefer a dedicated MP3 manager, Enqueue is the closest we've found to replacing iTunes and costs $9.99.
Utilities
Dropbox
If you have a work computer, a home computer, and a smartphone, then you know keeping files in sync across devices is a pain. Dropbox solves this by syncing any files you want across multiple computers for easy access anywhere you are. You get 2 GB for free, but it's easy to get free space.
uTorrent
For BitTorrent clients we're pretty split between uTorrent and Transmission. However, uTorrent wins out for having a ton of features, including a portable mode, complex bandwidth adjustment, and remote monitoring. If you prefer Usenet to BitTorrent, we'd suggest SABnzbd. If you combine either with Sickbeard or Couch Potato you can easily set up the ultimate automatic streaming machine.
Skitch
On the surface, Skitch isn't much more than a screen capture app, but it's also a way to quickly annotate an image, point something out, and share it instantly through Evernote. Screen grabbing isn't necessarily everyone's cup of tea, but drawing a moustache on a friend's face certainly is.
Growl
Growl is the standard for system notifications and pretty much every app out there supports it to some degree. When an app wants you to know something, it displays a small notification in the corner of your screen with Growl. These notifications might be emails, Twitter updates, upgrades, or whatever else. The newest version of Growl bumps it up to a paid download for $1.99, but users of OS 10.6 and 10.5 can still snag the free older versions. It's hard to say how useful Growl will be if you plan on upgrading to Mountain Lion, but if you don't, it's essential to keep track of all your notifications.
Crashplan
Crashplan is a versatile and easy to use backup service that's free as long as you're using an external hard drive. It's our preferred bulletproof backup system because even the paid tiers are cheaper than other options. You should backup your system often. Crashplan is the easiest way to do it.
Unarchiver
You probably download all sorts of archived files on a daily basis. The built-in OS X utility can handle its fair share of formats, but not everything. Unarchiver makes sure you're covered no matter what you download. The nice thing is that it works right in Finder, so you never even have to locate a seperate app.
The Extended Pack
Calendar
The built-in iCal app is great, but it doesn't offer a way to quickly get a look at your calendar. Calendar does just that. It's a tiny little app that works in conjunction with your iCal events, but it's great when you just need a quick look at your upcoming events.
Found
Found is a universal search app that allows you to quickly search files on your Google Drive, Dropbox, Gmail, and your Mac's hard drive. Found is just as responsive as Spotlight, but you get more options to quickly search through all the different places you store files. It also has a great shortcut where you can tap the Control key twice to pull up the search menu.
Cobook
The default Mac Address Book isn't bad, but Cobook blows it out of the water with its social media integration, automatic updates, and its fast search. The one downfall is that Cobook works in conjunction with Address Book for syncing, but as a speedy, simple, address book it's a good addition to any system.
CheatSheet
Keyboard shortcuts are awesome time savers, but they're incredibly easy to lose track of which shortcuts do what in different apps. CheatSheet offers up keyboard shortcuts for most popular apps when you hold down the Command key. If you're new to a Mac or you just downloaded a bunch of new apps, CheatSheet is handy to keep around.
Read Later
Read Later is a desktop viewer for articles you have saved in the bookmarking services Pocket and Instapaper. The interface is similar to what you find online, but you can download and save articles to your hard drive. This means you can catch up on reading even when you don't have an internet connection.
This list is hardly exclusive. There are plenty of apps we mentioned last year, but decided to exclude this year to highlight some newcomers.