This is the one I have, currently selling for £269.00 inc postage from ocuk.
The BFG 8800 GTX costs £396 inc postage so that's a saving of £127.00.
£127.00 would buy you a nice PSU.
I actually have a 700W modular Jeantech PSU (see my sig) not my usual first choice but I needed one in a hurry so popped down to PC World and paid about £85.00 for it. It's well built and works fine.
Obviously the GTX card is a better choice but is it worth the money?
Possibly, it's a hard choice. Personally I baulk at paying nearly four hundred quid just for a video card but that's the market I'm afraid.
As for waiting for a new card to come out, if you play the waiting game, you'll always be waiting for the next great thing to come out. With computers and computer components when you buy the latest you'll be lucky if it's top of the tree for three months.
And you really want better graphics right now don't you?
I have the GTS and all my games run flawlessly.
I have Oblivion Elder Scrolls Four maxed out and it looks gorgeous
So there you go, food for thought