My current system is an HP Media Center. I just got a 8600 GT Graphics card-need to upgrade the PSU before I install it since I only have a 300 in the standard system. I am also going to get a cheap AMD X 2 6000 from a friend that went to a Core Duo MB. Will 450 be enough? I am not a hardcore gamer-not going to do SLI or anything like that. I may play the occasional 3D game, but I mostly use it for internet and audio processing-I am a "amateur" musician.
Any assistance would be appreciated

check this out:

http://www.newegg.com/Product/Prod [...] 6817103941

for the price it dont get much better than that broooo

This will be able to run your system fine. Look mostly at the +12v rail(s) amps, not the total watts.

This one is actually a much better deal. Plenty of power. http://www.newegg.com/Product/Prod [...] 6817371007

Yes 450W will be fine. You have to watch the amps on the 12v line. My recommendation is the Corsair 450W VX which has 33 amps on the 12v line and you can get it from Dell for $59.95 after $10 MIR.

http://accessories.us.dell.com/sna [...] lid=585555

I have:

Athlon X2 6000 + o/c to 3.12
2GB DDR RAM (667)
250GB SATAII HDD
DVD/RW SATAII
GeForce 8600GT
External HDD powered by USB
Wireless PCI Card
17" Monitor

-- It's all running very stable (can game for hours no trouble) on a 380W supply. I went for a CoolerMaster eXtreme Power 380 (dunno if still available) - 450 is plenty in otherwords!