Uhh, there is plenty of reasons to have a computer of this caliber. You must have missed Ephialtes' thread about his new computer, now that could be considered overkill.
Hell, my new computer has an Intel Core i5 (2.67GHz/Quad Core), 4GB DDR2 RAM, an ATi Radeon 5800HD (Approx. Total Memory according to dxdiag, 1775MB) and a WD 1TB SATA HDD in an Antec 900 Case. I can easily get another hard drive when I need it, since the entirety of basically all my data fits in under 100GB right now this won't be until long after this entire rig is outdated and probably scrapped.
Also, I think that nVIDIA's new tech was CUDA, off the top of my head. Can't remember right.