I loved Craig's Hair Force One joke, but those two guys teasing each other during iWork demo were just annoying, that was too much.
Also, I think it was one of them going something like "it's just gor- beautiful." He probably realized he used "gorgeous" in previous sentence so he changed it to "beautiful"... Well, I didn't believe him.
That was Eddy Cue. He seemed to be uncomfortable in this situation because he was looking down at the teleprompter the whole time (hence the correction you noticed, and the flat jokes). Even though he's prominent in the company, I don't think he's been on stage much.
The other jokester was Roger Rosner (on the left in the "revise the record cover" demo, at 50 minutes into the keynote), who co-founded a startup called Lighthouse Design (http://www.langreiter.com/space/Lighthouse+Design), which, in dinosaur times, developed the presentation program Concurrence for NextStep. That's Roger at the top of the stairs in the photo above.
Concurrence eventually was rewritten at Jobs's request, and became Keynote. Roger also hasn't been on stage much, but he's a good guy, and a real developer, so cut him some slack. (Incidentally, the guy at the very bottom of the stairs is Jonathan Schwartz, who eventually became CEO of Sun, but was not really a developer.)
It seems like they realised that Craig's jokes went down well at WWDC/iPhone events so another presenter should try it too.
The whole presentation seemed too scripted. Most of the presenters are usually good but they were saying the wrong words and backtracking (your gor -beautiful example) all over the place.
Also, I think it was one of them going something like "it's just gor- beautiful." He probably realized he used "gorgeous" in previous sentence so he changed it to "beautiful"... Well, I didn't believe him.