Most of the time I keep them, as I will usually read them again one day.. and often find I get something different out of it the next time around.

If I really didnt like it, I will pass it on. I also used to have a book cafe down the road from where I lived that would pay for second hand books, albiet it wasn't a lot but it was often enough to cover one of their fantastic lazy Sunday breakfasts and coffee!!

I think I read somewhere about a book swap website... I have never checked it out though.