I was foolish enough, at least in hindsight, to get a 8800 GTS 640 about three months ago, but the new GTS 512 is saving me from getting burned too badly. I went eVGA, and I've got 18 days left so I'm stepping up the 512. Ironically this is a drop from a $395 card to a $355 card (and costing me around $20 in shipping) so I still got a little burned. On the other hand, I've enjoyed the card I have for 72 days now and for just $20 am getting the boost, so I'm just happy it came out in time.
I'm be sad I didn't wait longer when/if the 9xxx cards come out in Feb and there won't be an upgrade for me, but until then I'm going to keep feeling like I dodged a bullet.