Wow. I just read Gnome 2.30 will be Gnome 3.0. That means massive API breakage, probably a new major release of GTK and lots of application porting. I don't code GTK myself, but I can imagine the hughe amount of work that will probably have to be invested in getting a good amount of apps working.
Nevertheless, this also promises an opportunity to get away from some less-than-good design decisions from the past, getting your hands dirty with a new widget toolkit and maybe, maybe a better desktop ;-)
I'm anxious to hear more news about this!