I collect all sorts of crap. Mainly its media like games, laserdiscs (usually anime), DVDs, records (hip hop, comedy, childrens, house, new wave, 70s/80s rock), CDs (far too diverse to mention), and books (anime, manga, scifi, automobiles). I'm not really a huge hoarder of anything, and I'm not a completist of anything, but I have lots of crap either way.
I also collect Transformers, but I'm really really picky. I only buy what I absolutely love, and I only buy stuff complete. Some of my best stuff; US Metroplex in box, and JP Roadking in box. None of that Beast Wars type of garbage. All toys must leave the box and are rotated through display. I just like keeping the boxes for vintage stuff. Other toys; Gundam, Astroboy, Macross. I also do the whole
plastic model thing.