I do miss cmd-`, toggle through currently focused app windows from Mac, one of the few features that I did not get in my switch to Fedora 3 years ago.

Of course, so much more was gained, the point of no return has long been reached ;-) Now the question, to Gnome 3 or not to Gnome 3?

Am I going to freak out as a gnome-do + compiz + dual monitor (laptop + external) user, or, with time, one adjusts, and, like an arranged marriage, learns to love the other?

You may want to wait a bit if you are happy with gnome 2, since there are still stability and perf issues (at least in 3.1) the really bog difference is that window switching has mostly become a modal thing, which honestly isn't as bad as you would think once you get used to it