Those 6850's are going to be expensive, but I bet they drop the price on the 6800's when they come out, either way for my money I would go with the 6850, thats just me.
US$266, just like the Q6600. They'll have locked multipliers, apparently.
I wouldn't count on the "extreme" products (X6800, QX6700) getting cheaper. Intel seems to just stop producing extreme versions rather than cutting their prices. I could still get a Pentium EE for CDN $1200 up to a few weeks ago, if I really wanted it