All of my history books are on the shelf, but there are at least 100-200 more at home. It sounds nutty, but I can't wait for the day when I can just have them all together in one central location. I think part of this also came from the fact that I was at my adviser's house this weekend, and she has a beautiful library set up in her living room. I want a whole wall of books too!
I have all of my running medals on the bookcase. I keep them there as a reminder of what I've done, especially to remind me when I'm questioning my ability to do something (like finish these terms papers). I have my running books/magazines there too, which are my favorite thing to read before bed. My medieval toys are up there on the shelf too: my medieval action figures, and the witch doll my mentor gave me when I defended my senior thesis (on medieval witchcraft).
If anything, I know that I work well and write well when I'm inspired, and all of these things help to motivate me when I'm writing or need to get out the door for a run!