I have used Dell because currently they offer the best prices on pre-build computers.

Build Your Own Computer Dell™ Dimension 4600
- Pentium® 4 Processor at 2.8GHz with - Pentium® 4 Processor at 2.8GHz with
533MHz front side bus 533MHz front side bus
- 256MB Dual Channel DDR SDRAM at - 256MB Dual Channel DDR SDRAM at
333MHz (1x256M-better solution) 333MHz (2x128M)
- 40GB2 Ultra ATA/100 -Hard Drive (7200 - 40GB2 Ultra ATA/100 Hard Drive (7200
RPM) RPM)
- CD or DVD Drive - CD or DVD Drive  
- 1-5 year warranty on all parts   - 1 year warranty 
- Monitor - Free Shipping  
Price around $499- $599. (shipping - Monitor
included) Base Price $799
Time to build: 1-2 hours.  
   
As of April 22, 2004