These posts will mean more to you when ut2k7 comes out and you decide you have to start upgrading to either run it or get it to perform / look like you want it to. I'm not saying you will have to upgrade because I don't know everyone's specs, but if you do.. pay heed to the psu.
From pcpower.com (pc power and cooling psu site)
5. AN SLI CERTIFIED POWER SUPPLY WILL ALWAYS POWER HIGH-END GRAPHICS CARDS?
We went through three power supplies before we found one that consistently worked with these high-end graphics cards and an FX-60. We initially started with a Silverstone 600W SLI certified power supply, but running some games resulted in the system powering down under full load. We next moved onto a higher rated Thermaltake PurePower SLI certified 680W unit. But while most games ran most of the time, the system would still occasionally shut down. Finally, we ended up using PC Power and Cooling's massive TurboCool 850 SSI. This just goes to show that if you really want to build something that pushes the bleeding edge, make sure you have the right power supply.
ExtremeTech Review Feb 12, 2006