I like to keep all sorts of items I find interesting around me in the studio. It gets to be a bit cluttered but that's OK.
I read that Freud had a collection of figurines and here's a picture of Ray Bradbury in his office. He's even got a wonderful model of the Nautilus (behind the red dinosaur) he got while working for Disney. Anyway, these things are great to sketch and often show up in my artwork.