Doing a quick build on from part available at
http://www.newegg.com (Ordered a lot from them, always quick and reasonable.)
1 X INWIN ATX MID TOWER CASE MODEL # IW-S500P.300F - OEM
2 X Thermaltake 80X80X25mm FAN
1 X Abit KT7A - Via KT-133A 200/266MHZ FSB A Motherboard
1 X Geforce2 Titanium 64MB AGP
1 X 1.44 mb Floppy Diskette
1 X AMD Thunderbird 1.2GHz 266MHz Bus Socket A processor
1 X KINGSTON KVR133X64C3/256 VALUERAM 256MB PC133
1 X IBM EIDE HARD DRIVE 40GB 7200RPM
1 X LITE-ON LTR-24102B-02 24x10x40 CDRW
1 X TURTLE BEACH SANTA CRUZ sound card
1 X Thermaltake VOLCANO II. Heatsink
$677.00 before shipping charges and tax if you live in CA.
More or less the system I run with zero problems. Every bit of the above is upgradable which is the big advantage of putting together yourself. (BTW, the case listed above is simply wonderful. Easy to get into, plenty of room, easy to work in.)
Add another 256MB of ram and you can even run WWIIOnline :-/
YMMV