Lung cancer. ABC anchorguy, for those who don't know. Didn't really like him so much, but I met him once. He's just always been on since I can remember, and this happened fast.
http://www.cnn.com/2005/SHOWBIZ/TV/08/07/jennings.obit/index.html
http://www.cnn.com/2005/SHOWBIZ/TV/08/07/jennings.obit/index.html
R.I.P. sir.