i know i'll be repeating some things here, but, too bad lol
Boot Camp allows you to designate a portion of your Hard Drive as a windows partition. It also gets you started on the installation of XP or Vista (if using XP, it must be a disk that has Service Pack 2 or later on it).
Now, you can hold option key on the keyboard whenever your computer is starting up to select the operating system.
Alternatively, you can go to the "startup disk" preference pane in the System Preferences.
You should experience absolutely no performance hit whatsoever with boot camp.
Boot camp will NOT allow you to run Windows software simultaneously with OS X. It's one or the other, but restarting really shouldn't take too long.
Fusion and parallels allow you to run windows and OS X simultaneously, but you will see a performance hit. This is because Windows is running in emulation, not natively. Also, with parallels/fusion you have to designate a specific portion of your systems RAM to Windows.
Additionally, fusion and parallels may have problems with the 3D graphics in games.
I don't really think Direct X 10 is that big a deal right now. You'll probably run most games faster for now in XP.
The only game I know of that REQUIRES Vista is Halo 2 for Windows, and they had a ******** reason for doing so. Originally they claimed they were going to use DX 10 for it. Well guess what... by the time it was released, they had dropped that idea. The game uses DirectX 9.
BTW, you have one other option for gaming.... crossover (and their newly released "crossover for games."
Crossover is different than the other options stated here because it doesn't actually run a copy of Windows. Instead, it allows you to open up Windows applications from WITHIN OS X. I think it's supposed to be pretty seamless.
The catch is, Crossover is not compatible with everything, and you will see SOME performance hit with games, though nothing like if you were trying to run them through parallels/fusion.
Also, Crossover, does NOT require u to install a copy of windows. If you want to try it out you can go
here.
EDIT: and.... i just realized that this thread is 3 months old lol