Mary Sue: My pony character is an alicorn (to be fair: he was once a pegasus til some crazy expiriment resulted in a horn).
Most Wonderful Sound: A lot of these can be found for me. Aircraft engines (old and new), car engines (from Mustang v8's to roaring exotic v12's), gun shots (particularly of the Bang Bang BANG variety). Followed by...
Most Annoying Sound: Clicking, whistling, other things. Doesn't help that people do this on purpose to bug me on a consistent fucking basis.