I decided that now was the 11th hour to sell my 6800GT and get decent money out of it. Due to the 7800GT price drops and the new cards coming out.
So I ordered a $275 EVGA 7800GT (even has dual link) and sold my BFG 6800GT. The upgrade only cost me $50. Not bad for nearly double the performance, half the power consumption, transAA, full PVP (WMV HD is amazing with Purevideo), also the 7800GT will be holding its value longer now that the 7900s are coming out (more value holding than the GF6 series at least).
I'm happy, BF2, Q4, CSS and all my games run so much smoother. The GF7 is a much more refined product than the GF6.
Being a very recent 7800GT buyer, I felt the time was closing in before the 6800s dropped in value much too far.
One scenario I would forget about: having the 7900GTs out, and then proceeding to sell your 6800GT and expecting something like a $50 upgrade cost.
I wouldnt have done it if the upgrade wouldnt be around that price, because I dont want to buy a "whole new video card" right now (aka cost me $400).
Thinking the GF6 is going to hold its value when the 7900GT is out is wishful thinking.. its a nice thought to get away with it.. but I'm afraid the best bet for GF6 users who want to do a relatively cheap upgrade to the GF7 series should be motating ASAP.. it wont be happening for you after the 7900 launch. Might as well "settle" for the 7800.
If you have a spare video card you could sell your 6800GT now and use the spare until the 7900GT is out, but even then you wont get away with a $50 upgrade, you'll be looking at selling your 6800GT for about $220-250 today (on ebay) and buying the 7900GT (as everyone is scrambling for them and availability is low and prices high) for $400 or roundabouts.
Its not woth it.
Sell the GF6 now while they are still relatively "hot" and only 1 step behind the upgrade cycle, and buy the 7800GT while other people (like the ones in this forum) cant stop thinking about the incremental upgrade the 7900 and X1900 will give them.
Play the game, dont let the game play you!
2sense.
And this is all IMO of course.