Dai's choice of the Antec 430 (trio model ONLY) is a very solid choice
but for $79.00 after rebate you can buy the antec Trio 550 watt
either of the TRIO series units are
85% efficient >>>> thats very important!
The Antec True Power 550's are only 70% efficient which is the bare minimum to meet the PSU standard= not a good thing really
The unit P-gal has listed is a VERY high class unit; Seasonic is the KING or psu units IMHO
you cant go wrong with any of these discussed here; you could put on a blind fold; choose one and live happily ever after!
just for discussion sake: The Antec SP-500 is a medium quality unit at best / 70% efficiency rating
The coolermaster 500 watt I Green series (Igreen's
only) are 85% efficient units = nice unit
I am of the opinion (as well as a couple of our other staff members) that Enermax has lost their quality control in recent months, if you read thru several of the feedaback comments from various enermax units in Newegg listings you will see several "reviews" which stated early deaths, blew up, DOA when they opened the box. I used to love enermax units, but I think they have turned to cheaper components to cut cost. I dont buy them any more. Have a look at several of the units discussed by our staff members replies, there wont be much if any negative talk about them in the newegg reviews, they are all high quality units. I am running an Enermax now in this box, 600 watt Enermax 701 model, but I dont buy any more for my builds. All my high class units where the customer is not looking for cheap, all get Seasonic, Silverstone, Fortron ect
When I need to save bucks, the Antec Trio's are then up to bat. After that comes the 30 & 60 day warranty machines.
The entire Antec Tru-power line is medium & 70% eff
The super flower = scary
coolermaster other than IGreen series is scary
The OCZ units are very good, but I have a gut feeling that for the
money you can get more than 450 watts from the Igreen series or TRIO antecs?????
good luck; ask questions enjoy the research; I guarantee it will pay off for you! You have already tackled the steepest slope in this journey; knowing that you cant buy a good unit for under $70.00
Bravo 
ray: