CPU: Intel Core i5-3570K 3.4GHz Quad-Core Processor ($215.99 @ NCIX US)
Motherboard: ASRock Z75 Pro3 ATX LGA1155 Motherboard ($84.99 @ Newegg)
Memory: Kingston HyperX 8GB (2 x 4GB) DDR3-1600 Memory ($34.99 @ Newegg)
Storage: Seagate Barracuda 500GB 3.5" 7200RPM Internal Hard Drive ($59.99 @ NCIX US)
Video Card: EVGA GeForce GTX 660 Ti 2GB Video Card ($289.99 @ NCIX US)
Case: Cooler Master Elite 361 (Black) ATX Mini Tower Case ($49.99 @ Amazon)
Power Supply: Corsair 750W 80 PLUS Bronze Certified ATX12V / EPS12V Power Supply ($85.99 @ NCIX US)
My question is how long can I go on the power supply. I was originally planning on doing SLI with a different mobo, but decided it would be cheaper to get one card. I am planning on giving this to a cousin in 2 years and building a new one, so I don't really need to future proof it. On pcpartpicker, it says estimated Wattage = 327 Watts. I plan on overclocking (yes i have an extra fan/heatsink,) but I couldn't see myself needing more than 400 Watts total. I just wanted to get the community's opinion before I make a possibly big mistake. Thanks all!
That's a great build for price/performance. Like azeem40 said you won't need more than 400W, but I would go for 500W just to be safe and 500W PSU's tend to be of higher quality. Maybe get the 750W one you posted (it's good I know of it) if you want to be able to SLI/Crossfire eventually with this build.
While the GTX 660 Ti is a good card I *might* suggest looking at the Radeon 6950 instead. They're about equal, but it all comes down to the individual games. However, the 6950 overclocks like a BEAST so that might give it an edge if you plan on doing that.