I first encountered Letterman when I was in high school and he was doing "Late Night" after Carson.
That remains, to this day, the best late night show I've ever seen.
After the Leno fiasco and Carson left the air, I followed Dave over to CBS for the "Late Show." That was awesome, too. But he eventually lost his way, and the quality of the show dipped.
His monologue on the first episode back after 9/11 remains one of the most wonderful things I've ever seen on network TV.
I am now a fan of Fallon on the Tonight Show, but I still check in on Dave every once in a while, and he has actually seemed much looser lately, more like his old self.
Cheers, old friend. I hope you have health and happiness.