I have a dual 1.42 with two 200GB drives hardware striped (Sonnet) as a scratch disc for video editing, then two 180GB drives, one as a startup volume, the other running off its own Sonnet card.
Video editor, need performance. Extremely happy with my setup. All of the drives are Western Digital's Caviars with 8MB buffers. Buy your drives from Hypermicro. Research'em at storagereview.com.
Good luck.