Yeah, I found out about these yesterday ...
check it out
"But that says $689 .."
Unselect the nearly $300 support option that's marked by default and choose the no-cost option (something like parts for a year) and remember that the resulting $389-ish cost does NOT include the $100 mail-in rebate.
I haven't seen the 5% coupon so am not quite sure how you get from $289 to $269 but the free shipping is real, as is the free upgrade from a 1.8 GHz Celeron to a 2.4 GHz P4.
For most of us Linux hackers a decent $40 PCI graphics card's sufficient unless you plan to add a bunch of extra stuff. The basic box includes an on-board NIC and all the pieces are supported by Linux.
Buy a 256MB DDR stick from Crucial for about 25% less than Dell charges and you're in business with a nice box.
I don't know how many memory slots the machine has ... or if the MB supports USB ...