I'd probably go with the 7600GT. The cards are very close... The 7800 might be slightly better, but the 7600 requires MUCH less power and is newer.
__________________
Desktop * Athlon X2 4200 | 2G RAM | 160G HD | 7600GT
Laptop1 * C2D T5550 | 3G RAM | 120G HD | Intel x3100
Laptop2 * C2D T5250 | 2G RAM | 160G HD | Intel x3100
|