my music choices generally flow between the following:

• loud, violent rap music, such as eminem, wu tang, etc
• classical, such as wagner, rachmanninoff, debussy, and the popular ones like bach, beethoven
• frank sinatra, dean martin, louis armstrong, harry connick jr
• theme songs! there's nothing like sitting down and coding to the beat of duck tales, gummi bears, or the price is right... i also recommend the quantum leap theme, very good