I've always enjoyed the Letterman show.
To me, Leno is a pure stand-up comedian and Letterman a pure broadcaster, who happens to be very funny.
I don't see the staleness in Letterman's comedy. It has always been very original. And if it bogs down for some people, it could be in the routine of the bits. Some of the jokes on the show have been used awhile with different punch lines, ala the "squirrel with his nuts" routine, and the "words of wisdom" of Dr.Phil.
Leno's comedy bits don't seem as funny or original. And he is not much of an interviewer. Not much reason to watch
Jon Stewart is great and I was hoping he would get the show after Letterman that eventually went to Craig Killbored. Don't have cable, so can't see Stewert's show.
"The Larry Sanders Show" recently was picked up by the local Fox station and has been showing on the weekends. TeeHees a'plenty