+1 leo switched to bzr as well
+1
MySQL uses it: https://code.launchpad.net/mysql
Ubuntu also is running their entire operating system using it. Of course, they write bazaar, but still, you can get any program's entire revision history from them if need be.
Ohloh really needs this. There are so many awesome projects on Launchapd that ohloh isn't indexing because they're in bzr. And I'm moving a bunch of stuff over there. I really want to keep the ohloh stats up to date.
Come on guys, +1000 for bzr support.
Ohloh makes me understand why they chose that name ("loh" means lamer in russian).