I found this months ago on YouTube, and I still find myself watching it at least once a week. The song itself (Rachmaninoff Prelude Op. 23 No. 5) is fantastic, but Gilels' performance is simply perfect, with expression that blows away all the other ones I've heard. I had to go out and buy the music, but it's crazy hard – I still haven't gotten the first 30 seconds down yet.
Maybe it would help if I grew an awesome combover-style hairdo like his.