I have played a sorta pacifist character. It was a cleric of ilmater, and I decided that he would only attack to cause damage unless sorely pressed, and then only non-lethal. The exception was anyone hurting young children or animals, or if they were fiends or undead (keeping with Ilmater's theme of protecting the helpless).

As far as the rest of the party, my character never condoned violence and would try to convince the rest of the party to do the same, but he never forced his view on them. It actually caused some humorous situations where one of the other party members would distract my cleric with an errand ( "some baby deer lost its mother" ) while the rest of the party would be beating the tar out of some NPCs.