Jack Tripper is dead?!?

I was stunned this morning to hear that John Ritter died! As a child, I was a huge Three's Company fan and have always liked seeing him turn up in television shows (Ally McBeal and Scrubs, to name a couple) and movies. How sad to see a life cut short at such a young age (54 is certainly young when people are living well into their 80's these days). :(