I also have a small C: (10G) partition for the OS, which I image...since I only have a couple of hours a day to play, restoring an image saves me weeks of rebuilding from a formatted drive if I have to clean it for whatever reason (virus, etc).
My Raptor is actually partitioned in three: the D: drive will eventually serve as my Vista partition, so it's currently bare. Drive E: contains temp folders for all my ripping apps, and a few installed apps.
My second hard drive is for the pagefile, more installed apps, and storage.