Two GTX260 video cards operating in SLI mode will draw about 350 watts and 30 amps at full load. The rest of a high end system that is overclocked will draw about 250 watts. That comes out to 600 watts at full load. A good 700 watt cpu will be fine.
The CoolerMaster UCP 700 watt psu lists a series of four +12 volt rails rated at 19 amps each. I kind of wondered about the four rails at 19 amps each. Some of the advertising indicated it had one large 12 volt rail.
JonnyGuru.com did a technical review of of the psu just last month. During the test it was discovered the unit uses one big 12 volt output to supply the four 12 volt rails and the two VRM's. Here's a link to the complete review:http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story&reid=141
Do you already have the power supply?