do the dell deal, you can always add a second HD or more ram if you feel it necessary for less then dell will charge you
spend the 150 for the 5000+ core, the difference between the 3800 and 5000 at newegg is about 120 bucks, so for 150 its not that bad of a deal. stick with 1 gig ram, you can add a second gig if you feel the need for 65 bucks on your own (half what they want), for the HD, its up to you, i don't know if that case can fit a second, but if it can, stick with the 160, get yourself a 400 gig for 100 bucks to add to it, or add an external HD to the 250 gig upgrade. add $50 bucks to go with the 20 inch widescreen digital monitor, 40 more for the vid card, 30 for the dvd burner, and 10 for the optical mouse
799 total with the 250 gig HD, add say 100 bucks for some external or internal HD addition, and 65 for a second gig of ram, your still under 1000 with a pretty nice machine, and a plenty of workspace on a 20" panel