For me, Confessions era hands down - the, artwork, the tour - the entire era was so well done!
Xstatic was amazing also - it was so dark, so gritty, so raw, so dirty (in the sense it wasn't polished) - a complete change for Madonna.
Blame it on Rio - was just silly - V Magazine with Katy Perry was cool, but not really an installation and the Marilyn inspired recent shoot - could have been something better, but was a little amateurish in my view - not as polished as Confessions or X static.