Hey i couldnt find a thread specific to power supplies so i hope its ok to post this here. Im on a budget and will probably in the future post what im getting exactly for further help but right now im deciding what power supply i need. I plan on getting a i5 2500k or i5 2500/Something around that area of processors. I also plan to get a Gtx 660 when it comes out.
A build with a GTX 660 level graphics card will be fine with a quality 500w power supply. If you plan on upgrading to a high end card then 550 watts would be recommended. For 2 x cards in Sli 650-700 watts most likely. Here are some excellent 500w models.