I configured this system on the dell website, which came out to $853:
PROCESSOR Intel® Core™ 2 Duo E7400 (2.8GHz, 3M, L2Cache, 1066FSB) edit
OPERATING SYSTEM Genuine Windows Vista® Business Bonus-Windows XP Professional downgrade edit
WARRANTY & SERVICE 1 Year Basic Limited Warranty and 1 Year NBD On-Site Service edit
MEMORY 4GB Dual Channel DDR2 SDRAM 800MHz - 2DIMMs edit
PRODUCTIVITY SOFTWARE No Pre-installed Productivity Software edit
Dell Recommends
Microsoft Office Basic Microsoft Word, Excel, and Outlook PREINSTALLED!
Upgrade to Microsoft® Office Basic 2007 (Word, Excel, Outlook) [add $149]
MONITOR No Monitor edit
SECURITY McAfee Total Protection for Small Business 30-day Subscription edit
OPTICAL DRIVE Single Drive: 16X (DVD+/-RW) Burner Drive edit
HARD DRIVE 750GB Serial ATA Hard Drive (7200RPM) w/DataBurst Cache™ edit
VIDEO CARD 256MB ATI Radeon HD 3650 -supports DVI,DP,HDMI Connections edit
MEDIA READER No Media Reader edit
MODEM & WIRELESS No Modem Option edit
SOUND Integrated 5.1 Channel Audio
You could just get a basic $400 computer from Dell, but if you want to do anything more then browse the web it just won't cut it. Also, Dell does not offer 1066 RAM, or anything better then the Radeon 3650, so you will still have lower performance from the Dell.