I really, really like it :) It's my brother's name, so maybe I'm a little biased, but I like it a lot!
Although I personally like the full name
Peter best, I think the nn
Pete will be unavoidable, unfortunately. I can't really think of any other nn's, either :S Sorry!
If you ever decide to name a son
Peter, you can always call him
Peter in full yourself, but be prepared for other people to shorten it...