Brett,

My suggestion would be to set it up as follows:

1. 160 GB C drive for OS & Programs
2. 500 GB D drive for scratch/page file
3. 1.5 TB F drive (or any other letter for that matter) for video/audio and other media.

I would not use one 500 GB disk and partition it into two, better use your spare 160 for the C drive, that leaves you more than enough space and gives you an additional disk for page file and temp files on a separate physical disk.