So i've decided that i'm tired of my families crappy single core slow ass pc's. I've saved a bit of my cash to make a small fund in which a friend pointed out a website that has bare bone sets. He reccomended that I get one instead of buying a PC at a store. After some consideration, I've decided to follow his advice... but I need some help with my decisions since I've never had to do something like this before. So...

My budget: $420 (no job and cheap parents so yeah thats all i got)

Website for the bare bone set I picked: http://3btech.net/babocospamda1.html

So here's my choices so far...

Motherboard: 1 GIGABYTE 880GM-D2H (Did a bit of research, and from what i found it seemed to be a better choice than the other two)

CPU: Default choice (1 AMD Athlon II x4 645 @ 3.1GHz)

Power supply: 1 Viotek 550W (This is one of my issues I need help with. I'm not sure if thats enough, or should i pay a bit extra for 600 or the 800W?)

Memory: NONE. Instead I'm considering this: http://www.ebay.com/itm/4GB-DDR3-1333-Value-Memory-PC3-10600-Desktop-Ram-NEW-/190444817980?pt=LH_DefaultDomain_0&hash=item2c57654e3c However, I'm not certain if thats the best choice. I was going to get 2 of these to maximize the 8GB limit. Please help.

Hard Drive: 1 Seagate 1TB 7200RPM SATA New (Was leaning to 500GB but than again, for only a bit extra I could get a TB. Since I'm planning to hopefully use this PC for some time, the extra hard drive space would probally be benefical)

Hard Drive cooling: 1 Dual Fan Hard Drive Cooler For 1 Hard drive

Floppy/Flash card: None (i dont think i'll need this)

Drive: None (Planning to scrap the DVD/CD drive from my old PC)

Modem & Wireless Card: None

Cooling fan: 3 Generic Sleeve 80MM Case Fan

Operating System: None. I'm not a fan of Windows 7 or (ewww) Vista, so I'll probally use Windows XP as it is my most comfortable OS, however when I was researching about the mother board 1 GIGABYTE 880GM-D2H, there was a notice about 32 bit system not supporting over 4GB RAM. Is this true? Should I go with a 64 bit instead?

Warranty: Standard


Configured price:

$307.97 (+ roughly $40 from the 2 ram sticks)

Grand total: 347.97


So... those are my choices, now can someone who is much more knowledgeable in this help me, thanks!