I love "Letter B" as well! Quite a few of my favorite Muppet songs feature Richard doing lead vocals, I admit, lol. I completely agree that Richard is one of the best singers of the Muppeteers. There's something that I find cute about Dave's voice, but my favorite singers have always been Richard, Jerry and Steve. Their musicality, harmonies, and all-around lovely voices always just speak to me and touch my heart. "Mr. Bassman," "Free and High," "Just a Dream Away," "Wemblin' Fool," "Rama Lama Ding Dong," and the previously mentioned "Six String Orchestra" are a very short list of some of my all-time favorite songs just off the top of my head that really showcase how fantastic they are. There are so many more, too.