For a Dell, it's a great buy - and Dell is one of the best for prebuilts.
But, they're right. You could build a PC like this (scrap the P4 and go with an Athlon in that case - it'll save you!) for $800-$900. The only biggie on that is the 18" Flap Panel LCD Monitor. That kind of item carries a heft price, and I'd be awfully jealous of anyone with an 18" LCD.
Athlon XP 2700+ Thoroughbred Core
1 GB PC3200 DDR RAM
nVidia GeForce FX5200 PCI
120 GB HD
Windows 2000 Professional, SP4
Dual Monitors - Samsung Syncmaster 955DF 19\" flat screen and eMachines 17\"