You got a new Mac for Christmas? Awesome. But don't let Justin Long's smarmy face fool you, it doesn't just give you a warm hug and set itself up. Here are 10 things you need to do pronto:

1. Check Out Snow Leopard's Interface Tweaks: They're not life-altering, but Apple's spiffed up the OS X interface in a couple of ways in Snow Leopard. Notably, there's Dock Expose (which works like Windows 7's Aero Peek) to show you all the windows of open app by clicking and holding on its icon in the dock. Also, giant, scalable thumbnail previews.

2. Move All Your Stuff: The funny thing about switching OSes or moving to a new one is that it's really not hard anymore, since so much of the stuff we do is online. The most complicated gambit for most people, I'd wager, is moving your iTunes library to a new machine—especially going from Windows to Mac—since organizing that stuff (if you're anal about it like me) takes forever. Luckily, there's a hack for that. And if you're going from old Mac to new Mac, well it's pretty easy to move all your crap with the built-in Migration Assistant.

3. Learn What's Actually Under the Hood of Snow Leopard: Apple says a lot of the magic of Snow Leopard is actually under the hood, so you can't see it, like Grand Central Dispatch, which promises in the future to make applications use all of those cores in your machine that much better to become superfaster. Or OpenCL, which uses your graphics card for non-graphics applications to go more fasterer. And there's a whole bunch of other standards Apple's real big on too.

4. Don't Buy MobileMe, Sync Your Stuff With Yahoo or Google: Don't buy MobileMe. Instead, sync your contacts with Google, straight from Address Book, and use Google Sync to deliver 'em to your phone. Same deal with calendars—use the open standard CalDAV to sync iCal with Google or Yahoo, which is as simple as putting in your account info now. And you can upload photos to Flickr directly from iPhoto. Online storage? That's free too.

5. Install Windows: Whether you do it through Boot Camp so you can play PC games ('cause gaming on a Mac sucks, at best) or use Parallels or Fusions to virtualize it and run alongside your Mac apps, with Windows 7 being $30 with a valid .edu address, there's no reason not to. It's even easier to move your Windows apps and files over that you wanna keep if you're making the slow transition, with Parallels Switch edition, which has a handy USB transfer tool.

6. Back Up to Any NAS With Time Machine: Time Machine, OS X's built-in backup, is indispensable. Unfortunately, if you wanna do it over the network, it's kinda limited, unless you know what you're doing. After you figure out your network storage of choice (HP's Windows Home Server with Time Machine compatibility is a damn good option; and for those on a budget, there's Iomega's ix2 200), it takes just a few minutes a couple of lines of code in Terminal to get your Time Machine backup going on any NAS you please.

7. Make It Play Nice With PCs On Your Network: If you get a NAS, you obviously don't have to worry about moving crap back and forth directly between your Macs and PCs, but if you want a method that will work every single time, this is how to do it. It's progressively easier with newer versions of Windows—stuff seems to just work more often.

8. Forget Apple TV, Stream to Your Xbox or PS3: If you've already got an Xbox 360 or PS3 (who doesn't?) there's no reason to bother with another media streamer, even if you're ditching Windows. The programs Connect 360 and Rivet will stream music, movies and photos from your Mac to your Xbox for $20. For the PS3, there's MediaLink, from the guys who make Connect 360, which does pretty much the same deal, but with slightly better integration with iTunes and iPhoto. The P2P app Vuze—which is free—also streams videos to Xbox 360 and PS3 from any OS it runs on, but obviously it's a little less feature-rich.

9. Download the Best Free Software: At first, there seems to be less freeware on a Mac, but you just need to know where to look. Lifehacker's essential free apps has you covered on everything from the best IM app (Adium) to better disc burning (Burn) to video playback (VLC, of course).

10. Remote Control It: Sure, you could shell out for MobileMe to use Back to My Mac—except, you shouldn't—but why bother when you do the same thing and remote control your computer from anywhere with VNC? An afternoon and you're done.

That's it from us. Share your own tips and tricks in the comments, and Merry Christmas!