That's a bummer to hear.
As far as comedic television actors, Don Knotts was pretty much at the top of the mountain. "The Andy Griffith Show" wouldn't have been anything without Knotts playing the funny man to Andy's straight man. Knotts won 5 Emmys for playing Barney.
I was reading some comments about his passing and someone summed it up - You'd be hard pressed to find someone who didn't like Don Knotts.
I suggest everyone watch "Pleasantville", if you haven't already. It was really one of his last memorable roles - playing a TV repairman, who was responsible for sending the two main characters into the world of a 1950's sitcom.
Watch that or one of his many films roles. Most people will remember his always as Barney, but he had a big career out of that.