On a recent Late Show, David Letterman was setting up a highlight reel featuring the exploits of his longtime stage manager Biff Henderson. Dave called his burly, grey-haired friend "a real fixture on the show — and like so many other fixtures of this show, more beloved, really, than me." (Cue President Barack Obama quipping that "Mainly, I came by to say goodbye to Biff and Paul [Shaffer].")

Whether or not that's true, the comment reinforced the fact that when Letterman signs off on May 20th, we're not just losing him; we're also saying goodbye to a deep bench of fantastic sidekicks, second bananas and average Joes (and/or Sirajuls) who've played the straight man and taken part in the host's shenanigans for the past 33 years. This list honors 10 of the most enduring supporting characters in the Dave-iverse — everybody from a brusque cue-card holder to our best Bud.