I sense another happy sr1710nx owner!
Remember that for a video card with lots of great big hairy man-pipes you're going to need a studly power supply. The delta 250 watt PS in that box is a quality unit, but it's not going to feed a ravenous card like a 6800 of any flavor. A 6600GT mmmmay work, but I wouldn't bet money on it.
Didja see my thread in hot deals? The egg still has a bunch of refurb 6600 non-GT and X600s in the $60-70 range. For old games like HL2 and KOTOR it'll be plenty.
I've been giving the integrated X200 chipset a spin, and it shockingly manages to run things I wouldn't expect it to. Far Cry is borderline playable at 800x600, all eye candy off.
Of course, dual channel low latency PC3200 ram may have something to do with that. =)