I dont think ANY apple computers are good for gaming. But thats just my opinion. And as for OS compatibility, yeah. Apples newer computers are aimed for networking. Apple is making their computers more compatible with other electronics. But Intel Core Duo would be faster.
Well now that Apple allows the use of Windows XP through BootCamp, playing PC games isn't bad. The Intel Core Duo and ATI Mobility Radeon X1600 Pro it has can do a decent job of playing games and movies.
Apple computers are usually the best for networking. It's quick and easy to setup, but I just don't like Airport's speed. Anyhow, I still prefer good 'ol Windows for networking. Easier to tweak and optimize.
Oh, I also might add that if you're going to buy an Apple Macbook and you're looking for good performance, just run Windows XP. Yes, running Windows XP on BootCamp is actually faster than running apps on Mac OS X.