If you're switching for games, I'd rethink it.
1. Only a handful of PC games are converted to the Mac.
2. When converted to a Mac, the game will generally have been out for the PC for a year or so.
3. Often the conversions are not very good, so system specs for games can be horrendously high.
4. Many shops sell PC games, Mac games have to be ordered from the web or found in very rare specialist retailers.
5. The PC game market is competitive, so you can find bargains or reductions on even new games. Mac games are expensive when released and generally just stay that way.
I like Mac's, my love for my powerbook borders on the fetishistic, but they're not gaming machines. Don't listen to the "the Mac gets the good PC games" argument because it's pointless, the bottom line is that the PC gets ALL the games (variety is the spice-o-life), they're much cheaper and they're easier to get hold of.