i think the best choice would be beethoven op.7 as somebody previous mentioned...i really don't understand why people tend to choose overplayed sonatas such as moonlight, pathetique..
beethoven op.7 is very demanding one but fairly managable, very beautiful. besides it's like jackpot on auditions and competitions if played well.
another one is Les Adieux, although more played and IMO more complicated then op.7
good luck!