I wish to be a guitar. People play with me all the time, I can make all the noise I want, and when I get older my value goes up and I'm known as "vintage"
I'd probably be a simple diary or sketchbook that's generally ignored, but occasionally picked up and examined by someone curious or bored for a little while until they find out what I'm all about and throw me away in fear and/or disgust.
That or I'd be a strange little figurine, possibly a Halloween decoration or piece of merchandise from a Tim Burton movie.
Urban Fantasy, High Fantasy, Epic Quest, Sci-Fi, Time Travel and World Hopping, Steampunk, Action/Adventure, Modern Drama, Mystery, Slice of Life, Romance, and many more.
I keep coming up with things and then discarding them
Pillow; soft and fluffy and comforting... but I'd get drooled and god-knows-what-else'd on all the time :(
Pencil: content to live my days until I am retirement length, aide to education and creativity and the quick jotting down of phone numbers. Buuut I'd get chewed on and stuck up noses
After thinking about it way too hard I guess I'd be a bowl. Serving my purpose holding cold cereal and hot soup, with an eventual quick and painless death by a crash on the floor.
In all seriousness though, a record. Something outdated and warped and completely unusable but you don't want to throw it away because it might be valueable but you sure as hell don't want it hanging around. In the end you keep the record sleeve in came in but you throw the vinyl away because it's worthless to you. You got what you needed out of it and now you can get the same music on youtube.