I have a number of small collections,
music - LP and CD probably about a thousand or so, mainly alternative, indie, chill-out and rock
Board games - getting close to about 200 or so. (no, none of them are for kids!)
Lego - an extensive collection of minifigures and quite a few sets (mainly collector sets)
Books - I read a lot of science fiction and historical fiction (like the bible ) my collection is divided into the pile by my bed I haven't read and the stuff on my shelves that I have read.
Geological specimens - I have a small collection of fossils, rocks and minerals.
Video games and consoles - I have too many consoles to attach to my TV (and my TV has a lot of inputs) and too many games (if you talk to my wife!)
Painted toy soldiers - I have a very small collection of painted figures and a very large collection of ones I should be painting!
I don't think any are particularly out of hand and they do fit in my house!