Video Card Suggestion

Hello everyone, I'm in the market for a new video card (upgrading from my 8600GT) and was wondering if I could get some suggestions.

I'm pretty much stuck on either getting an ATI 4870 or GTX 260 216, but cannot decide which based on the price and power requirements. (I know they are basically equal in performance, I'm not here to debate that).

I know for a fact that my OCZ StealthXStream 600Watt can support the 4870, but can it do a GTX 260 like this? I need to know for certain, as the life of the rest of my PC depends on my PSU.
»www.newegg.com/Product/Product.a···14127409

Now, I was just about to get the 4870 last weekend, when ATI announced the price cuts, but held back thinking they were not officially out yet. I was wrong. Now, apparently, the manufacturers aren't cutting the prices, so a 4870 1GB (sapphire) is 197.99 with shipping on newegg.

What I'm basically asking is if I should get the GTX 260 (if I can support it) right now for 159.99 after MIR, or wait for a future ATI price cut. Do you think the 4890 or whatever they will call it, that comes out in April, will lower the 4870 prices down a significant amount?

Thanks for the advice and info, I'm really stuck right now. I don't want to impulse buy, but I don't want to wait forever.
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Specs:
Core 2 Duo E6750 @ 3.2ghz
XFX 8600GT @ 620/900
2GB DDR2-800
Vista Home Premium 32
Gigabyte P35-DS3R rev 1
OCZ StealthXStream 600Watt (quad +12V 18amps/per.)