I collect (and have been collecting) all types of stuff over the years.
As a kid, I used to collect those "TV Guides" you get with your Sunday newspaper. I did that from the summer of 1986-1990. The stack was HUGE! I think my mother threw them away after that.
Currently I collect:
Transformers
Currency (I am an amateur numismatician). I have some old coins and currency, some commemorative, and some foreign (Thai Bhat, Indian rupees, Bahama dollars, etc).
Black Heritage stamps.
This is just to name a few.