itd be really tight with the 460. not really enough wattage on the PCI-e rail output. a 550w is barely enough with no headroom for anything else. id think the minimum should be a 600w. corsair, silverstone, seasonic would be some strong choices.
your understanding of how much power PC hardware draws is very poor
at load he would just barely break 300w (if that since the i7-920 draws more power) total power and during gaming he would be well under the mark
to answer the OP question, yest the CM PSU will work but I would start saving for a better unit sooner rather then later.
CPU: Intel Core i7-920 @ 3.33GHz
Motherboard: Asus Rampage II Extreme
Chipset Drivers: Intel 188.8.131.525 (Intel)
Hard Disk: OCZ Summit (120GB)