Antec has actually been putting out some nice Green model PSUs for relatively little cash. I'd recommend at least getting one of those to try out. I have this same unit:
Newegg.com - Antec EarthWatts Green EA-430D Green 430W Continuous power ATX12V v2.3 / EPS 12V 80 PLUS BRONZE Certified Active PFC Power Supply
in one of my servers, and it's a great little PSU. Cheap too. It's in a price range that I normally tell folks to avoid, but we use Antec 300's and 400's at work without any issues at all, so I'm comfortable recommending them.
I'm not trying to discount Echo's statements, by the way. Just that in my experience, overtaxing a PSU is a bad investment for your PC. Hate to see folks fry a system, whether it happens right away, over time, or never.