GTX295 or GTX460?

I currently have 260 core 216 in my system. I was going to buy a new card and use the 260 as a physx card.

Basically I was trying to decide between these two cards. I can get a GTX295 for $200 from a guy from my local LAN. Or I can get a 1GB GTX460 for $220.

I only have a 750W power supply. So that makes me nervous in going for the 295. I also can't find anywhere that directly compares the performance of the two cards. It seems like the 295 just narrowly edges out the 460 from what I can tell. If it is just a very narrow difference I would rather go for the card that uses half the power. Then in the future I could get another 460 and SLI them if I need to squeeze more performance from this computer before upgrading to a whole new computer.

I guess I should say I run games at 1680x1050.

The rest of my system
Intel Q6600
Asus P5N-D motherboard
4GB DDR2-800
750W Power supply