Since this is a pretty visible change for a lot of people, I thought I'd send a top level note. The GTK UI is now committed and is the default UI provided it's available.
For anyone counting, it's been a little more than 7 years in the making: http://article.gmane.org/gmane.comp.emulators.qemu/9726 If you want to try it, make sure you have the gtk-2.0 development packages installed and the VTE development packages. Regards, Anthony Liguori