Video card: Either the EVGA or XFX. The XFX is 10% faster on the ram, but less people like it. Their RMA is kinda a hastle (know from experince)
193$
http://www.newegg.com/app/ViewProductDesc.asp?description=14-150-085&depa=0
192$
http://www.newegg.com/app/ViewProductDesc.asp?description=14-130-220&depa=0
CPU: AMD 35watt 2400+ mobile. Great overclocker, and with it's support for older ram and not DDR400, this makes overclocking EASY. Can give the 3.8ghz p4 a run for it's money.
89$
http://www.newegg.com/app/ViewProductDesc.asp?description=19-103-439&depa=0
MOBO: Some model of the abit nf-7
62$-92$
Suggested one: 83$
http://www.newegg.com/app/ViewProductDesc.asp?description=13-127-166&depa=0
RAM: Just any stick that you can find. Corsair Value select or some other ram would be a good ram.
50$ a stick, you only need 1, but suggest to upgrade to 2 later.
http://www.newegg.com
Heatsink: This is a good one. I have SKT 939 version and it rocks. Will handle your overclockign goodness
http://www.newegg.com/app/ViewProductDesc.asp?description=35-106-035&depa=0
33$
Power Supply: Thermaltake TD-420AD. Nice power and Nice price
38$
http://www.newegg.com/app/ViewProductDesc.asp?description=17-153-006&depa=0
Case: Whatever, use a peice of plyword for what I care.
EDIT: This is 486 Dollars with one stick of 512 Ram. Use the other 120$ for more ram, or fans and a case. Oh yeah, i forgot a hard drive, get one at your discretion, and you most likely have a spare CD-ROM laying around.
Please note that this setup is one made for overclocking, since mobile chips run extremely cool and stable, they can give a 3.8GHZ Intel a run for it's money when overclocked