I just wanted to learn how to build a PC from scratch, and I set out to build the cheapest usable computer I could, with as many new parts as possible. Everything except the HDD on there is listed at purchase price after rebates - the HDD i just used and old one I already had, with Windows installed. It took me around two hours and so far it has been working great :)
Parts are listed on the left, the CPU+Motherboard combo was on sale at Frys for $79.99 (64 after MIR), and the PSU cost $24 (15.99 after MIR).
It didn't work as smooth as I would like right off the bat, because the old HDD had a bunch of things that ran on startup, but killing a few unwanted processes got the memory utilization down and it's doing far better since. A Full HD video does peg the CPU to 98% however and there is the odd stutrer. 720p does okay,. Overall the CPU runs very quiet, and temps under load seem reasonable.
It was a lot of fun building this computer, posting some pictures here. Thoughts if I could I have done better with this budget? And how I can improve performance? Haven't OC'd yet.