Last week on Late Show, Letterman estimated that there have been 105,000 guests on the different iterations of his talk shows. (During the CBS primetime special earlier in the week, Ray Romano mentioned the host had actually interviewed something closer to 18,000 folks; Dave is apparently determined to crack wise until the very end.) That's a lot of chitchat, but not all those guests are created equal. Below is a list of the 10 guests whose appearance on the show always filled us with the most excitement and anticipation. Note: This doesn't mean that these 10 were the most frequent guests — but when they were going to show up on Late Night or Late Show, we made sure to tune in.