Ever since I was young I've been obsessed with collecting something whether it be coins, pokemon cards, etc etc.
At the moment I go to the local comic store each week to pick up a few titles, I'd say I have probably 1.5k+ comics or so.
I also do comic book art, I used to get one or two commissions every once in a while, but that was way before I discovered I could get free sketches at signings and whatnot in a book - which was much more convient + free. I have a crapload in my sketch book, theme is "movie characters".
I used to do action figures, I would still like to but it's too costly. Of course I do not open them. For some reason I do not like exposing things to the world and whatnot, it disturbs me. I have them all hung on a wall.
My favorite thing to collect is, of course, autographs. I try to go to signings as much as I can, but going on 1 hour train to NYC + $17 roundtrip ticket is costly. I've only done one premiere (The Dark Knight) but I don't do those kinds of things because they come up on short notice, and also they're not guaranteed; thus wasting money. I haven't gotten an autograph in person in a long time since Ed Westwick (Gossip Girl), Daniel Dae Kim(Lost, and Boondock Saints Troy Duffy and Sean Patrick Flannery at NY Comic Con, so while I wait for something good to come up I started sending requests though the mail. Yeah, ttm stuff may not be legit, but I know which ones are not secretarial, preprints, or autopens.
I've built up a decent collection, I have like, Nicolas Cage, Bill Cosby, Michael Madsen, Gene Hackman, cast of TDK, Spike Lee, Hideo Kojima, Hayden Panettiere, Bruce Campbell, Kristen Bell, etc etc etc.