What is the best 500w PSU right now?
Seasonic is top rated, this model Is insainly efficient and has a 30buck rebate 
See the efficiency rating HERE
That Seasonic is very nice.
Here’s a couple of other options that should work well that are a bit cheaper.
Enhance E5150GH
http://www.ewiz.com/detail.php?name=PS-E5150GH
Corsair 450VX (33A on the +12V rail)
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139003
If you do some research on user reviews, you won’t find any negatives for the Corsair… depending on your hardware it’s your option which one to go for…
I now have the 520w (3 months) after having had generic brands in the past. Very quiet and can handle my gaming pc faultlessly.
Thanks everyone. I am going to use Seasonic in my main PC and Corsair in my HTPC. I have been looking at lists of the best ones, but at least here I can get actual feedback from people using the items.