Even my longer pieces I have in my library, I can't listen to over and over again. With most musical pieces, once you lose that marvel of listening to it the first time, the melodies and tone of the piece become bland and you want something better. But finding something better is freaking hard, isn't it?
Anyway.
Sibelius's Violin Concerto in D Minor, which I think is the piece I've listened to the absolute most, must be performed by Heifetz though. All of Sibelius's pieces, like his Second Symphony, have such great sounds that it's easy to listen to them over and over.
EDIT: Another.