The hard drive I am using is some old, cheap 120GB Hitachi, and I have an M-Audio Delta 1010LT and Geforce 6600GT, all of which I bought years ago and never felt the need to upgrade, despite none of it being anything special by today's standards.
Here's what I got for my friend, whose is slightly better than mine, but almost identical, and what I would have done if I hadn't been in dire need of a computer. Mine has the lower model of the processor, which is nearly identical, but gets stuck at about 3 gHz, the ASUS equivalent of his motherboard, and the same RAM, but not rated at as good of timings stock. My stuff that I actually use now I had to buy at stores around here, so I didn't get to pick and choose as much, but this all came from Newegg.
http://www.newegg.com/Product/Product.a ... 6819116052
That one will overclock beyond 3 gHz with the appropriate motherboard, just using the included POS heatsink, without even trying. You can probably get them to 4 gHz if you're retarded enough, as it's actually identical to the upper end Core 2 Duos, just with less L2 cache and the clock set low stock.
http://www.newegg.com/Product/Product.a ... 6820145034
Cheap as hell, but still good for using with an overclocked system.
http://www.newegg.com/Product/Product.a ... 6813128050
It was actually the model one step lower, which was maybe $30 cheaper, but it mysteriously vanished. I'd probably get that one now, anyways, because it barely costs any more, and technically supports a 1600 mHz front side bus, which should work with new processors for years to come.
He also got a Geforce 8800GT, a 22" monitor, 250GB HD, and of course a case, power supply, DVD writer, and whatever else I may be leaving out, and like I said, I think it was under $1,000. While this may not be recording related at all, he can play that ridiculous Crysis game with the graphics maxed, which is one of the most demanding things I could think of.
And this wasn't hard to set up, either, even though its performance is pretty much a product of significant overclocking. I just turned the front side bus speed up, and left the rest on automatic to adjust for it, and it was fine.
With my setup, I can run something like 80-90 Waves plug-ins, most of them being CPU hogging compressors, reverbs, vocoders, and whatnot, before it becomes overloaded. I may have reused some stuff, but the computer essentially only cost $200. To make the entire thing, sans a recording interface, probably could have been done for $350.