I collect books too- it's in my blood. Everyone in my family reads constantly, and as I was growing up my house would always have at least one room with floor to ceiling bookshelves, crammed with Atlases, novels, dictionaries, cookbooks, fieldguides... you name it, we have it.
Sometimes I get books just to have them: ie- I have a first edition of Tim O'Brien's
The Things They Carried, and I have a few copies of
Zen and the Art of Motorcycle Maintenance. Gathering books in the great quantities that I do is especially dangerous because I was also a philosophy major

I will leave you to imagine how heavy a trunk full of philosophy texts can be (whoever said knowledge was heavy stuff wasn't kidding

)
I've taken to leaving my books at my parent's house until I buy a place, or at least sign a lease for more than 6 months at a time.