Agreed, a really fine finale. I hadn't been watching the show (I'll catch it on dvd) but I am glad to have seen the ending live, to share in the moment as it happened. Bravo.
Bill Lawrence said in an interview that Frasier wanted to do it, but he was filming a movie at the time. Masi Oka (Franklyn) and Sarah Lancaster (Gift Shop Girl) really wanted to do it, but NBC wouldn't grant them an exception on their exclusive contracts for "Heroes" and "Chuck", respectively. Tom Cavanagh made a special effort so that his cameo could happen.
That's weird that the post of Chuck's that I was quoting got screwed up like that, here's what it was supposed to say: It was recorded for Shall We Dance? and as far as I know, the songs on the soundtrack album have never been made available induvidually. I've loved that cover ever since seeing the movie.