There are plenty of songs I've lost interest in, but the song that comes to mind that I used to love but now skip whenever I come across it is "Give It Away" by the Red Hot Chili Peppers. I still will listen to tracks from Mother's Milk on occasion, but generally avoid anything after that (other than my liking "Road Trippin'" for a few years after it came out).
http://www.youtube.com/watch?v=EaNICEA98gw
http://www.youtube.com/watch?v=EaNICEA98gw