First you need to determine home much power your system actually requires:http://web.aanet.com.au/SnooP/psucalc.php
Second you need to determine which high quality power supply meets your requirements. Corsair and PC Power & Cooling both offer high quality psu's. They consistently earn high marks in technical reviews and comparisons. They are very stable and reliable. The psu's come in a variety of wattages and configurations.
Generally we find that when people ask about psu's they usually overestimate their power requirements. It happens all the time at this forum.