I'm rather bored right now, so might as well talk about that 2011 Comic Con poster I bought, and eventually ramble on about the only three people with slight hoarding issues in my life...
For one, I didn't buy it because of an over obsession with ponies. I bought two, and you'll see why later. I framed one and hung it in my room, and left the other in the (rather crude) box I got it in. Of everyone I know, my dad, my dad's friend and I have this little hoarder issue of varying severity. I'm the lowest on that list, I'm a collector. If there's something limited edition and it isn't beyond expensive and I have some cash, I'll buy it simply because "rare" items intrigue me. It's the same reason I bought every one of the pony propaganda posters that guy on deviantArt was selling, and the Comic Con posters.
My dad is medium on the chart, he keeps a lot of boxes from things he buys. In his garage rafters, right above the door, it's filled with boxes of varying sizes. Package boxes, vacuum cleaner boxes, microwave oven boxes, you name it. The boxes are the biggest offender I've seen, but there's probably other things like the whole totes of C++ books he sold only recently and the bookshelf that has the entire bottom row packed with books for learning Chinese from his military linguist days.
His friend, however, has a real collecting problem. He has 40 something guitars, a drum set and god knows what else and he doesn't even play any of those instruments. My dad says he becomes obsessed with whatever he likes at the time, and won't stop until long after. My dad has 15 guitars and 12 cases, but he actually plays guitar. He said himself he's not very good at it (though he does play a pretty good Crazy Train) but atleast he uses them. None of us have a *real* hoarding issue, we don't collect total garbage and keep it until we die. Our stuff is actually worth something in a collector's sense and a material sense.
...Kudos if you actually listened to my random wall of text.