Most of the stuff in my room is part of a larger collective, so i'd say in the 100-200 disk range. That being said, i'm sure that about 10% of those DVDs get 95% of the usage. We have plenty of movies, but the stuff that gets played the most is mostly TV shows. I'm bored so i'm going to list some of our favorite stuff to watch...
Kids in the Hall: Season 1
Kids in the Hall: Brain Candy
MXC: Seasons 1 and 3 (still don't have season 2 for some reason...)
Ren and Stimpy: Season 1 and half... or whatever.
Mr. Show: Seasons 1-3
Monty Python's Flying Circus: All four seasons
Manborg (It's a real movie, i promise.)
AXE GIANT: The Wrath of Paul Bunyan
Drunk History: Seasons 1 and 2
Yu-Gi-Oh: Volumes 4 and 15 (best 2$ i ever spent!)
And of course, the most used disk of them all, by a HUGE lead...
TROPIC THUNDER (THE BEST MOVIE EVER MADE, IF YOU DIDN'T KNOW)
I also would like to note that if The JonTron Show was available in disk format i would buy everything, in triplicate.