Why do people spend that much money on a Mac just to throw it away by installing Windows? Learn OSX or buy a Dell. Nobody buys a Mac for games anyway.
But if you're going to, get at least the $2500 model. Twice the system memory and twice the GFX card memory. The CPU is also faster, jumping up from 2.16GHz to 2.33GHz.
The $2800 model has 160GB harddrive rather than a 120GB, a 17" screen instead of 15", a slightly faster dvd drive, and an extra usb port. If you don't feel you need the 17" screen, then don't waste another $300 because the extra model features aside from the screen aren't much. (its also 1 pound heavier)
If it were me, I'd get the 17". I bought a 17" G4 powerbook little over a year ago and love the size of the screen on that baby. Only mine came with a mere 512mb of ram, which I upgraded myself because Apple wants a small fortune for upgrading ram in-house.
"Using Unix is the computing equivalent of listening only to music by David Cassidy" - Rob Pike