Graphics Card Upgrade, will Corsair TX650W take the load?

Here is my system build so far:

HAF 912+ Midi Tower Case (High Air Flow)
2 x 200mm Coolermaster Megaflow Fans (Front & Top)
1 x 120mm Case Fan (Rear)
1 x 140mm Case Fan (Side)
Intel iSeries i7 930 Processor (Plan to OC to 4.2GHz)
Coolermaster V6GT CPU Cooler
Gigabyte GA-X58-UD3R Motherboard
Corsair TX650W PSU

So my plan at the end of the month is to get 2 x Western Digital 'Caviar Black' 1TB hard drives and put them in RAID 0. I am also looking at getting either the Dominator GT 2000MHz Ram or some ram of equal speed and quality and either a LG DVD/RW or Sony DVD/RW. Now my problem lies in what graphics card to get, I've had a look at a lot of benchmarks, videos and forums and from what I can gather the best bang for buck is the GTX 460 768MB version in SLi, BUT, I am worried that my PSU may not be able to handle the SLi, SO, I have also been looking at the Sapphire AMD ATi Radeon HD5870 'Vapor-X' Card. I am fully open to suggestions and my budget for the graphics card(s) is between £250 and £350 any suggestions would be greatly appreciated.

You want 2 GTX 460s? The PSU should easily support 1, 2 and you may want to step up to a 750W or greater, but you might still be ok with 650. Easiest way to figure this out is to try and roughly calculate power usage. Some components state their idle/load usage in the specs, others you have to estimate. You want a PSU that can handle everything at load, but if you're just a little under (say you calculate you need 675W) then you'll be fine the majority of the time (overclocking might push you over though).