Corsair and thermaltake are sufficient PSU's. 600 watts can be sufficient but if you plan upgrading your system, I would suggest going for a higher wattage. It is only a few bucks more expensive but can save you a lot of trouble. I would suggest one of these two units, by Corsair:
And, if you are really going to build a strong gaming system and overclock, go for a 1200W modular power supply:http://www.ebxtechshop.com/en/product.php?id=104244
I bought an Antec 650W power supply from a local compter store a few months ago and it was barely enough to power my overclocked i7.