If you're sold on that XPS configuration, you can get that machine with a couple upgrades, including the 250 MB HD and a 3 year warranty for $1500.

Apply this coupon (F1B0649QN51B2Z) to this system

You'll want to upgrade the video and the speakers to match the system you had configured. I'd also consider the $40 to upgrade to a 320GB RAID-0 array. This will give you a nice performance boost.