Do you have a budget?
Rosewill Capstone 650W 80Plus Gold $100 ($14 shipping)http://www.newegg.ca/Product/Product.aspx?Item=N82E16817182071
The 550W version is the same price so I recommended this one.
You should not be put off my the fact that it is a Rosewill branded unit. The actual manufacturer is Super Flower and the platform is known as Golden Green.
I have never seen a negative review for a Golden Green based unit (NZXT Hale90, Kingwin Lazer Gold, Lazer Platinum, Super Flower branded units, Sentey Golden Steel Power).
Even the Rosewill Capstone 750W got a positive review at Jonnyguru, the only aspect of performance that was unusual for this platform was that ripple and noise was only half the spec at full load (which is still pretty good), rather than well under half the spec at full load.