Even though gnome-shell is really only a preview of what is to come for gnome 3.0 and it's still buggy and sometimes not completely stable perhaps, I really like it.
When I first saw the screenshots I was less then impressed, I thought it didn't at all look like anything new or innovative, but rather messy and confusing. But me being ever interested in new things and all I just had to give it a try (the gnome-panel look was starting to bore me).
Installing was easy
sudo apt-get install gnome-shell
and starting it afterwards was easy too
Though first I had to disable compiz, which I don't really use anyway.
I was also using avant-window-navigator, which disappeared on me but still kept part of my notification area to itself. So the time after that I first closed AWN and all was as it should be.
I didn't feel like having to manually start gnome-shell every time I logged in so I started looking into a way to replace metacity and gnome-panel with gnome-shell and found that this could be done by editing you gconf (with, for example, gconf-editor) and setting the /desktop/gnome/session/required_components/windowmanager key from metacity to gnome-shell.
Of course, since it is a composited window manager you need a video card and driver that can handle screen compositing.