I've got all the Star Trek movies. They're the recently released two-disk-each collector's series. I've been slowly going through all the little documentaries on the bonus disks. Lots of interesting stuff there, the best of which (and I could have died laughing when I saw this) was on the bonus disk for The Wrath of Khan. That being Leonard Nimoy wearing an outrageously tacky pin-striped suit to an interview. I plan to gradually acquire all the TV series on DVD.
I know lots of Trekkies IRL. Some of them are okay, but most are a bunch of annoying wankers completely caught-up in the politics of their fan organizations. (Organized fandom sucks.) I'd go to their meetings and they'd spend hours dicking around with their bylaws and other bullshit. I'd often completely forget it's a club for people who all like a TV show. These days I stay away from them and hang out with sci-fi fans of other genres. If any of you decide to hang out with other sci-fi fans IRL, be very careful.
Star Wars... Got the box-set of DVDs the day it was released, and also have them on LaserDisc.
There are lots of documentaries about both Star Wars and Star Trek that you can get on DVD, some of them pretty cheap. Just take a look on Amazon. Gotta have some of those, too.
The Matrix... Ultimate edition box-set on HD-DVD. (And, one of these days I'll purchase a Blu-Ray player for all those movies that didn't come out on HD-DVD. For now, I'm just taking advantage of cheap HD-DVDs that sellers are trying to get rid of. Back in January, I bought an HD-DVD player knowing it was going to lose to Blu-Ray, so I could have something to watch those "fire sale" disks on.)
Aside from sci-fi, I also collect independent flicks, mainly from Odessa and Troma. Also, two of my favorite rock bands (Talking Heads and Devo) have movies associated with them. I haven't seen either yet, but they're on my must-have list. One of them is True Stories, which uses Talking Heads songs in its soundtrack. Another, from Devo, is titled something like The Complete Truth About De-Evolution.
I could ramble on but y'all get the idea.