If you plan to run Sims 2, Quake 4, Doom 3, or the upcoming Civilization IV on the Mac Platform, pass on the Macbook.  Anything that relies on accelerated graphics will not run optimally on this machine.

On the other hand, the MacBook is still very nice in terms of affordability. If you don't mind not having the "latest and greatest," there are plenty of good games that are quite playable on this machine. Just make sure you've maxed out your RAM. A recent test using games based on the Quake 3 engine demonstrated this quite clearly. On a "medium" setting with 512 MB of RAM, a typical game played at 52 frames per second. However, installing the maximum 2 GB resulted in a doubling of performance, with a rate of 98 frames per second.

Other titles that work well on the MacBook are Jedi Knight II and Jedi Academy, X-Plane, and Railroad Tycoon 3. There is also a new Universal version of Quake II that plays quite well, although the full retail version of the game is required to use the Universal version. Generally, these games work better on the MacBook (which "borrows" RAM from the motherboard for graphics applications)  than on the old G4 using an high-powered graphics card.

Again, if you're thinking about running Quake 4 or Doom 3, find a different machine. MacBook may run these games at their lowest screen resolution with image quality and details at their lowest settings - but if one must do that, why bother? If it's a quality gaming experience you're after, stick with the Xbox 360 or Playstation2 - they're cheaper, and the graphics are amazing on a  high definition television. If, for whatever reason, you must do must gaming on a Mac however, you should at least purchase the MacBook Pro - and this may still be underpowered for most of today's games.  For the best Mac gaming experience, spend a nickel and get the Quad 2.5GHz PowerPC G5. The ultra Intel-based machine will be coming out soon, so you could probably get a heck of a deal on a Power PC G5 on an auction site.

If, on the other hand, you're just an occasional gamer,  the MacBook will probably work for you. Just remember to install the maximum RAM, and understand that the machine has limitations that game-specific consoles do not.