i just built a 600 dollar system. actually, a lil less:
all prices in final, shipped.
ECS K7S5A 72
Radeon 32 DDR 80
IBM 60 GXP 7200 rpm 40 gig hd 108
floppy (bought teac from buy.com cuz i had gift certificates, you can get for...) 10
Volcano 6cu 7k rpm 15 bucks Axiontech
Acrtic SilverII 8 bucks Axiontech
onboard sound
onboard lan
56k winmodem free with MIR, you can ifnd a lot of these
Que! 24X burner with Burnproof - rebadged Sanyo 70
Cyberdrives 56x eide cd rom 30 buy.com (free withmy GC) you can find else where for like 25
256 mb 2100 DDR crucial 34 use webpromo link, and ebates.com rebate
Athlon 1.2 MP 166 bucks butyou can get a cheaper, faster processor, i need mp cuz i'm builing a dual proc. system -- 1.4 ghz athlon is 100 bucks frys combo think is 150
you can find a reasonable 19 inch monitor for around 170 shipped check hot deals
Enlight 300 Watt 7237 case, one fan standard, i bought upgraded case fan (exhaust and intake now, good cooling) 70 bucks
total = 592. correct me if i'm wrong, but this would be hard to beat. i did not count monitor price. if you want that too under 600, build a duron system, get a no name brand case, and get a cheaper CDRW. i wouldn't reccomend it though. unless mentioned, items are from newegg.com