2 XFX Radeon HD 6850 775MHZ 1GB 4.0GHZ GDDR5 in CrossFire: $200 CAD, $400 total.
My info is based on the November 2010 best GPU for the money roundup, and some reviews.
Are there any among these cards that will prove a worthwhile upgrade over the gtx 275? I'm getting ready for Diablo 3 (not too worried about that), but also Crysis II. I've been playing the beta for Rift, and it's been playing in the low teens sometimes. Obviously the fact that it's in beta testing has something to do with it.
Nonetheless, any advice would be appreciated. Thanks for reading!
HD6850 crossfire is your best bet for high performance. The current performance it offers is also going to get better over time.
For a single card grab an HD5870.
HD 6850 Crossfire seems to be the perfect choice for your requirements.I would also overclock that CPU.