i'll give you 3 options here..
there are 8 parts total to this build, and i'll assume $12.50 average discount per part.
1) same components you listed, plus:
LG DVD-WR $46
Western Digital 250gb SATA II 16MB $115
BFG 7600GT $255
total: $1465 - $100 (your special discount) = $1365
2) similar price as 1; with the following changes.
Thermaltake Soprano case silver $100
X2 3800+ $338
Lg DVD-WR $46
Western Digital 250gb SATAII 16MB $115
ASUS 58NX AMD 939 mobo $120
Kingston 2gb ram kit $209
Antec TruePower II 480watt powersupply $96
XFX Geforce 7900GT $385
total: $1409 - $100 (your discount) = $1309
3) similar to build 2, but w/ cheaper vid card.
Thermaltake Soprano case silver $100
X2 3800+ $338
Lg DVD-WR $46
Western Digital 250gb SATAII 16MB $115
ASUS 58NX AMD 939 mobo $120
Kingston 2gb ram kit $209
Antec TruePower II 480watt powersupply $96
BFG Geforce 7600GTX $255 (the site says GTX, but i think its just GT, lol)
total: $1279 - $100 (your discount) = $1179
in the pieces i picked, i didn't think SLI mobo was worth the extra $$. also since budget is sorta tight i thought cheaper psu and case would not be bad, since they're still high quality. its really all upto you. sorry for taking so long to reply, looks likeyou've gone to sleep now, hehe. out of the 3 builds, i'd lean towards build #2. you can play games REAAAL nice with a 7900gt. but if you're strapped for cash, build #3 is still good. and if you just love that antec case, and you can't live w/o the ocz psu, then of course #1 will be your choice.
edit: i'll probably be in deep deep sleep by the time you decide on what to do, hehe. if you have an HDD already then you could save $100 right there, or if you don't nee dvd-wr and you have a cd-rom lying around, you could save $50. you can keep goin through it and look for ways to reduce the price; and also you can mix and match b/w my 3 builds for whatever suits you. if you had to reduce the price in something, it would probably be better to reduce aesthetics than performance, but since this is for your gf, maybe not, hehe.. good luck in whatever it is you choose. if you get $400 for your rig i think you'd be really lucky, lol. if that happens, i think buying this new comp should definitely happen. peace.