I dunno, I figure once I get a serious home theater the whole collection will be put to good use. I had one for awhile but had to take it down through moving into a few different houses. Doesn't fit as well as it did the first house, and I can't put surround sound up. Once I get my own place though, home theater > kitchen.
Anyway, there are a few flicks I've bought but have yet to watch. Saving Private Ryan being one. Fantastic movie, but I feel I wouldn't give it justice unless I watched it in a home theater the next time I do. Also, it's one of those movies you don't want to see too often, but enjoy it the times you do. Also, ROTK:EE I haven't watched. Again, that's a home theater movie

What else.. Grave of the Fireflies I've only watched 1 and a half times. Watched Back to the Future trilogy once only. And.. Matrix Reloaded I watched but once. For some reason I thought they might turn it around in Revolutions and I'd want the whole collection. NOPE. I only wish I owned the first Matrix. I'd trade Reloaded for the better picture quality of the first Matrix.
Hmm, and Looney Tunes volume 2 I havent watched through. Don't regret it because there's some awesome documentaries, a few amazing cartoons I've watched multiple times, and a lot of good stuff in it. Volume 1 I watched all of though. Oh, and the Mickey Mouse black and white collection. More just a collector's item. I actually watched every Goofy cartoon. Oh, and I forget why or when I got the Samurai Jack dvd. Not the season collection, the flick. But it's been used once and probably won't be again. Also, Rain Man I bought blindly and I really don't think it's that great of a movie, despite a great performance by Hoffman. Won't get too many viewings if more than one. Rundown, bought it on a cheap deal when it was rented out. Kind of a dumb one. Actually, real dumb. Suburban Commando was bought for $5 but I've yet to watch it. Good cheese though. Predator as well, which has a lot of Arnold kicking ass. Need only Commando, the perfect one liner blow shit up action movie. After that my Arnold collection's complete, though I haven't watched his movies too often.
That's about it. Oh, and I once bought my little sister the first 2 Harry Potter movies, when she was all hyped for the 3rd one. Never watched one of em. That was over a year and a half ago, when I thought I'd start getting birthday gifts for siblings despite having no money. That didn't take long to stop.