Burnin -- it's $499 if you can find one. I recommend the BFG b/c it's overclocked to 425/1100 out of the box, with a great additional overclocking utility included that'll optimize the card. If you've got money to burn in addition to oil, BFG offers a card with a factory-built-in water block for cooling (so no fan and no noise) for about $700. I've read people getting that thing up near 500/1250!!!!
On-ramp -- amen about Far Cry. The physics models are 2nd to none, the environments are spectacular and the game is very non-linear. There was a beta patch that applied Shader Model 3.0 for Far Cry, but they pulled it b/c it was crashing a lot on ATI cards. Freaking Canadians.
Doom3 is a bit of a let-down game-play wise (very linear, no ability to "lean", unimaginative weapons, etc.) but it is a stunning looking game. I actually think Painkiller is as fun, and it's much less sophisticated. I'm hoping Half Life 2 rocks. But I risk a serious Vitamin D deficiency if it does.
The guy who wrote Riva Tuner said he's got a means to unlock a 6800 GT's 4 "extra" pipelines so it'll run as an Ultra -- keep checking
www.nvnews.net to see when it's posted. Good Luck!
JP