really depends what you want to spend? Money no object then look at the protek pro20 or pro40 or if your looking to be as cheap as possible look into Computer Server power supplies. HP makes a Server power supply that is 575 watts/47a and its very very simple to mod it to work. Lots of people have gone that route and been more than happy, oh and you can pick them up on Ebay for around $20 SHIPPED.

http://www.ebay.com/itm/DPS-600PB-HP...item41634be666