If you are in to multi-tasking, as i am, then you would benefit from a duallie. Yes , that's right, dual processors! No, forget about intels' overpriced xeon crap, get a Tyan MPX chipset board and 2 AMD processors, preferably MP's, but XP's or even Durons will work. You can build, or have a local shop build you a dream duallie system with SMP luvin for less than that Dell junk.
http://www.tyan.com/products/html/tigermpx.html