2 PC campaign, Which Class?

[Jack Simth]

I would agree with that sentiment. With just two PCs, you're going to be lacking somewhere no matter what, unless the DM creates a couple of NPCs to be voices in the party and/or to round things out.

Well... if you go Gestalt, a Dwarven Druid//Wizard and a Dwarven Druid//Ninja will cover all party roles quite nicely at most levels - You have two 3/4ths healers, a sneak, an Arcanist, and (thanks to the Animal Companions) two 2/3rds tanks, and they can play tank directly (wildshape) when they need.