Like last year's most popular Mac downloads, this list is based on the popularity of apps we've covered in 2009, regardless of the original release date of the app. Many were brand new this year, while others were solid updates to popular software.
Snow Leopard: The Feisty Kitty That Could (and No, It's Not Quite Free, Either)
The release of Snow Leopard was nearly as big a deal for Mac users this year as Windows 7 for Windows folks, and while it was never strictly a download (unless you grabbed it from less reputable means), it's worth highlighting. Over the course of the year, we helped out by prepping your Mac for Snow Leopard, highlighted its biggest improvements, and held your hand while upgrading. If you didn't want to pony up for Apple hardware, we even showed you how to install Snow Leopard on your Hackintosh PC, no hacking required—and luckily for the frugal among us (no, this one's not free, but it was a big deal in the OS X world so we figured we'd include it), the $29 upgrade disc worked whether or not you were upgrading from Leopard.
2009 Was Still a Year of the Jailbreak
The iPhone hardware may be getting better and better, but Apple still hasn't gotten any better at opening up the app store to, oh, competition. As long as that's the case, jailbreaking apps like PwnageTool and QuickPwn will still be extremely popular. Magnifique Customizes Your OS X Theme
The release of Snow Leopard didn't do all that much to change Leopard's spots, but Magnifique certainly does. This free skinning app is full of user-generated Leopard-customizing goodies. Note: Magnifique does not support Snow Leopard, so you'll want to steer clear of it if you've upgraded. Unfortunately the Magnifique development seems to be at a standstill at the moment.
DoubleTwist May Be the Coolest Universal Media Manager Ever
People fed up with iTunes' restrictive stance on non-Apple devices (see Apple and Palms' dance, for example) were very interested in doubleTwist, a universal media manager that automatically converts files to the appropriate formats and seamlessly syncs them to your PSP, Android device, BlackBerry, and more.
Google Quick Search Like Quicksilver from Google 
A lot of people were disappointed to learn about Quicksilver's grim future a while back, but many of you were heartened to learn that Quicksilver's creator had released a similar tool working with Google called Quick Search Box. Then again, it appears Quicksilver's not entirely dead just yet.
Pollux Automatically Cleans and Tags Your iTunes Library 
For all the access to track metadata contained in the iTunes store, iTunes is a slouch at cleaning and tagging mislabeled or poorly labeled tunes. Pollux was an absolutely killer iTunes supplement that grabbed song, artist, album, and other metadata names, along with lyrics and album art, quickly and accurately. The problem? Shortly after we highlighted it, Pollux was shut down because the APIs it accessed stopped letting it access them for free. We liked Pollux better, but if you're looking for something similar, check out TuneUp (free and pay versions available).
Picasa for Mac Beta Released, First Look 
After years of Windows-only support, Google released the first Mac version of Picasa at the beginning of the year, and it didn't take long before the majority of our Mac readers preferred it to iPhoto. You go, Google.
Quicksilver Releases Update, Improves Performance
Just when we thought Quicksilver was no more, it turns out that several contributors are continuing occasional development over at social coding web site GitHub. Their latest release brought on some solid performance improvements, and it worked well (for us at least) with Snow Leopard.
Glims Turns Safari into a Browser Worth Using 
Free Safari plug-in Glims adds a handful of new features to Safari, giving it the kind of features one might expect from a more, ahem, customizable browser—for those of you who still prefer Safari to its more feature-rich counterparts.
