What (If Any) Classes do you Ban or Alter?

[Gambit]

Our main DM only bans gunslingers and firearms (he uses a longstanding homebrew world)...we've never had anyone roll a summoner.

[Mordo the Spaz - Forum Troll]

Only allow barbarians.

Really, play an All Barbarian Party and you'll never go back...

[davidvs]

I'm always a Player. But the one time I was going to GM Pathfinder I was going to require all the PCs to start with one level of Bard. There are enough archetypes and races that it still allows variety from first level, and it would produce a party with extra skills and wand use.

Of course, the adventures were designed with that kind of party in mind.

[Grey Lensman]

I'm almost always a player, but my group has a Forgotten Realms game and a Golarion game running on different nights.

Both of them ban the Synthesist.

The FR game bans the Gunslinger, and all firearms based archetypes, due to the nature of the Realms

3PP stuff is allowed, provided the GM is allowed to look at it before the game, and such stuff is available to any player at the table.