This is my first build and the PSU is the only thing I haven't decided on. I'll be running an E6600 (overclocked), an X1900XTX, an ASUS P5W DH Deluxe, at most two optical drives and at most two hard drives (IDE and SATA respectively). How much power do I need? I've been looking at an Antec TruepowerII (550 Watts) and an OCZ GameXStream (600 Watts). Aside from wattage, the GameXStream has two more 12v rails, and I've heard it is a great power supply, but I don't want to get more than I need. Oh, and for the record, I'll probably upgrade my power supply before I get a DirectX10 video card, as the situation warrants. Thanks In advance.