I don't know when power supplies became something people fretted over. I've been building machines in the military and private sector for 15 years and it has always been "a power supply is a power supply." The cheaper, the better has always been my thing. As long as you have the wattage and with the low power consumption of the intel Core i chips and motherboards you most likely do. I just built a brand new system and I think a 300W ps was all I had and found it in the garage in a pile and it works just peachy.
In other words, put your money in memory or SSD, after you hit 16Gb of RAM, put every extra dollar in SSD or GPU if that's your thing.