get a Antec 550Watt 2.0 if you can its a good PSU neighbor has one if you cant get that then go for a FSP Group 450Watt I have it running a 7800GT smoothly so they are both under a 100USD
You do not need to get uber OCing RAM since you stated you wont be overclocking a bit, I would get valueselect ram, 4x 512 sticks Corsair, they suck for OCing, but I dont OC and they work wonders for me.