ENERMAX Noisetaker II EG495P-VE ATX12V 485W Power Supply 115/230 V - Retail
I calculated my wattage requirements three times-- it's somewhere between 303 and 340. So 485 should be great. No point in getting something huge, since I don't know when I'll be upgrading to a new motherboard and cpu, or what my needs might be when I do. In the same breath, I don't want to cheap out, either. My computer is my livelihood, and reliability is key.
It's pricier than some others, but heck, it's Enermax. Can't go wrong with Enermax.
...well, as long as you do your research ;)
Oh, and if you ever have ANY questions about power supplies, please feel free to ask me. I'm here to help :)