The Macbook is the low end Mac laptop. Its great for productivity, etc. However I would suggest getting a high end imac 27" with the 1GB ATI video chip for gaming. I don't do much gaming anymore, but its the video card, or video chip that makes most of the difference when it comes to good graphics.
I know that the Mac Books do not do well with heavy graphics, and were never meant to be gaming machines. Laptops in general were never really meant for gaming as is. The mac Book pro may be a better choice as far as laptops go.
If you run windows through Boot Camp, you will have no problems that you wouldn't experience on any windows machine. Like crashing, freezing and needing to shut down and reboot from sleep, viruses that never stop coming, and all the other wonderful things that go with Windows.
If you want great gaming experiences go buy a PS3, there set up just for that.