I was very happy to see Jon Batiste (I really thought he'd have come out for the Questionert the night before), and Elvis Costello was a lovely surprise. I'd have appreciated Sir Paul more if he hadn't been on SNL the previous weekend, but that's just me.
I doubt this was at all intentional, but when the studio was shrunk down to a snow globe at the end, I immediately thought of the end of SCG's run on The Late Late Show (at least partly because it aired the same night The Colbert Report ended), which also featured a snow globe, but of Craig's desk and such.
I assume that the intent of running through Hello Goodbye twice was to edit them together in post? When Craig taped the opening song in his final show (I was in the audience for that segment), they also did it twice, but it was because something went wrong the first time around. Whatever it was wasn't obvious to the audience.
David