Well, Steam being Mac-friendly now, as well as many Valve games, gaming is no longer Mac's disadvantage IMO. As for me, I wouldn't buy a Mac desktop because I prefer custom building/tinkering, and I wouldn't buy a Mac laptop because I'll be spending more on things that don't really matter to me like looks. Above all, I'm too used to Windows to willingly take away the comfort of it away from myself. But yeah, Macs aren't bad at all. It's just that they have some fans that make them look bad, but then again, so does Windows (like the people who write Macs off as garbage based on principle instead of evidence).
I'm not going to enter (I hope) in a big discussion like all the other threads but here's a few points...
Components: same as the other parts available off the shelf/in non-apple computers
Casing: for the pros it's one nice piece of aluminum with a nice screen and awesome touchpad
OS: I will go out and say the best all around desktop OS if you know how to use it. Very nice and easy to work with GUI and what runs under the hood is one finely tuned and well coded piece of software. The kernel(s) under it are a wonder (if you know how they work of course...).
Software: Most of the software that will run on OSX (except companies like MS) will follow Apple's standards and simply won't be trash. Some will of course; avoid them. For the rest you won't be disapointed.
Gaming: There's some game but sincerely forget about the choice of game you have on that platform compared to Windows.
Virus/Malware/other craps: Forget about them for a while still. There's some but yay for signed binaries checking, and sandboxing so you can say that there's virtually none for now.
I seriously doubt that you haven't had a crash in the last 9 years either
To the point though.
I'm a long time mac user (was bread on them), but I got my own gaming rig. I use both daily (See signature).
1. They do just kinda work (not saying they don't crash, but just that everything in the OS, and a lot of 3rd party stuff integrates a lot better into the OS)
2. OS X is more streamlined, and faster on comparable hardware (faster in OS response, and boot times etc.). For example, my work laptop (not in the signature) is a 3.0 GHz C2D Macbook Pro with 4 GB's of DDR3 RAM, and a 256 GB SSD (I can't tell you which one, came with the computer, and I'm not gonna open it up to look, although that's quite easy), beats my brothers Dell XPS i7 720, 4 GB's DDR3, and this Corsair 128 GB SSD. In response time, boot time, etc. (OS speeds)
3. Build Quality is excellent. By this I mean the computer's construction, not the components
4. Exceptional Customer Support - if you have a problem and are under warrenty it will be fixed and fast. Dealt with them on numerous occasions for issues ranging from a bad RAM stick, to a dying GPU in my Mac Pro.
5. Multitouch. In my opinion the best multitouch available on any laptop. I think most would agree.
1. PRICE. If your looking at a pure hardware standpoint they are very overpriced. Some people (like me) take into account the build construction (all their laptops are less then an 1" thick, and have at least 7 hour batteries), which offsets the cost somewhat, but you definitely pay an apple tax.
2. Gaming. I've got several thousand posts on a mac gaming site, and know my stuff. The gaming scene exists on mac, but is relatively young (Steam came out just in the spring, and before that there was hardly anything. It's getting better now, but if you call yourself a gamer get a PC (which is what I did)
3. GPU drivers (nvidia). OS X does not use DX (MS would never let them), they use OpenGL, and apple likes to control GPU driver updates, so they are very few and far between (like 2 per year). A good mac port of game (like Bioshock) will get about 15% better performance in windows. Poor ports will get double or triple the framerate in windows. Which means that unless you have a top end iMac, a Mac Pro, or a mid-high end MBP, your not playing any new releases in OS X.
4. No Blu-Ray, if thats any factor to you (isn't for me)
5. Well I can almost guarantee you that you won't get a virus in the immediate future, but there is no real good virus/malware/etc. protection like there is in windows.
Really comes down to personal preference of the OS. I can tell you that OS X is VERY fast, once you learn the shortcuts, especially with a trackpad or 5 button mouse. Not saying Win7 is slow, but OS X just has that blazing speed. Oh, Apple's apps work better is OS X (safari, itunes, etc. cuz obviously they get more love there).
Umm, well since I'm a mac guy: get a mac :bleh: but seriously, look at your needs and wants, balance them, and get the computer that you think fits best.