You shouldnt have ann issue.
I use Photoshop CS2 and none of my work is on the same drive as CS2. Matter of fact nothing is on the same drive as where the main Apps are installed. I install apps either on my XP drive (C
or my games drive (D
. Everything else has it own drive. Music, Pics, Movies.....
So when i run WMP to watch a movie or play mp3's they are not on the same drive. So there should be any issue.
As for the partition slpit it with 100GB for vids then another 100for data and the other 50GB can be for backup or storage.