Well, I finally pulled the trigger.
After seeing all of the awesome overclocking results with the 470s after making some voltage adjustments with MSI Afterburner, I started to keep my eyes open for some nice deals.
... and then I found this:
$339 for an EVGA GTX 470 from mwave if you have a membership. Well, I just bought a package of dirt cheap SATA cables from them a couple weeks ago and started a membership at that time. On top of all that, I got a $10 off $100 coupon when I started the membership.
So, I just got an EVGA GTX 470 for $329 shipped.
I should be able to get around $150 for my 260 on ebay, so I can more than double my graphics performance for a difference of $180. Not bad at all IMO. It should go very nicely with the low profile GTS 250 I just bought for a Physx card.
Can't wait to get my card!