I stumbled upon a list of cult films on Wikipedia and spent my break checking off all the ones I've seen in their entirety. There's a lot of popular movies on it like The Dark Knight but I guess Heath Ledger's performance has given it a cultish enough following to be on there. Regardless I checked off about 433 movies and I probably own 70% of them. I wondered how many movies I own and it has to be at least 500 according to this list!
I added the Critters and Wishmaster collections to this year's Christmas/birthday list so that could be eight more.