Eh, I don't know about the "$1000 for what everyone's getting rid of". I built my current one for $1300 a year ago, and that's including LCD monitor, surround speakers. Since then, it got mangled by UPS, and I built it again with the insurance check and some salvaged parts, so I have right now:
P4 3.4GHz on an Intel board
1GB PC2700 (I bought this for an AMD processor, so that's why the lower speed)
gForce 5900 128MB DDR
MAYA 5.1 Surround Card
40 GB HDD
160 GB HDD
LiteOn DVD+/- Burner
Altec Lansing 5.1 surround speakers
17" LCD screen
Epson C66 Inkjet
I also got a copy of Win2K Pro free through the CS department at school, since my tuition partially goes to pay outrageous fees for MSDN access
So, even if you factor in the cost I would have paid to buy a copy of Windows, I ended up paying around $1500 a year ago for a computer most people were paying $2500 to get from Dell/Compaq/et. al.
I also (re)built my parent's computer over the summer, from an Athlon 733MHz/128MB they got 5 years ago to a AthlonXP 3000+/512MB DDR. New case, board, processor, memory, and a cheap video card came out to a whopping $300. For a machine they most likely won't need to replace for another five years (heck, they didn't really even need to replace the 733, but something got fried on the board).