I'm close to purchasing my first Mac. Which HD are you all ordering for your Mac Pro if your not using their stock? I was thinking about ordering and 500-750GB for the main, a 150GB Raptor for my PC junk and using the stock for Time Machine. Is it ok if I use the Stock for Time Machine if my Main HD (the one i'm gonna back up) is larger? I was thinking about a WD (good history with them). Which WD HD would u suggest? The Raptor came in the mail yesterday. I'm just trying to pick the Main HD to order before my Mac Pro arrives.