My late chess instructor Richard Verber used to motivate me with classical music CDs for good showings. Unfortunately, I cannot listen to this anymore because it causes me to revert to thought processes from before I began work on AI. But others don't necessarily have this limitation, so perhaps some recommendations could be useful. I am unable to recall the vast majority of the songs I liked but I do remember a few of the more common titles. Please note I can't remember specific recordings, so I'm just grabbing whatever pops up on Youtube. (BTW, if you like to listen to Youtube music on your computer there's a good Firefox extension for downloading videos off of youtube. And then there are other converter tools which can convert from video formats into audio formats. Ping me if you want help setting them up.)
My favorite song was Tchaikovsky's Violin Concerto in D Major. Here's a version I think played by Maxim Vengerov who I saw in concert. Can't believe I remembered Vengerov's name out of the blue (that's what I mean by reversion, it starts priming memories).
Also liked Dvorak's Slavonic Dances No. 3 and 4.
I recall at the apex of my interest in classical being completely blown away by Marjan Mozetich's Affairs of the Heart, but I tried to listen to it recently and it did nothing for me. Sadly I seem to have lost my classical music sensibilities.
Elgar's Nimrod (from Enigma Variations)
Of course, Barber's Adagio for Strings (although that was later, in college):
I also liked Schubert's Unfinished Symphony 2nd movement, Dvorak's From the New World Symphony, Beethoven's 5th Symphony 2nd movement, Bach's Jesu Joy of Man's Desiring and possibly the Brandenburg Concertos (although I think they may kind of drone on), certainly other Bach songs I can't remember, etc etc. Richard Verber said that the best piece ever composed was Bach's Mass in B Minor. My Dad liked Beethoven's 3rd Eroica.