What size PSU do you need?
The size will be determined by the graphics card/s you intend to use.
Here is a handy chart to determine that:http://www.realhardtechx.com/index_archivos/Page362.htm
As to quality, that is a very good... really essential goal.
Pick a tier 1 or 2 unit from this list if you can.
Tier 3 will be ok too for a small budget:http://www.eggxpert.com/forums/thread/323050.aspx
I might take a guess that a Corsair CX430W unit might fit the bill.http://www.newegg.com/Product/Product.aspx?Item=N82E16817139026