I like zealots. They always hate heathens with a passion. If you stay in no religion they probably attack a heathen anyway. If you adopt their religion you have an almost-friendly AI from religion alone.
And I like people like Gilga, Hamm, Kubilai. They have good early fav civics wich you are going to run anyway most of the times.
Obviously the worst are GK, Shaka and Montezuma. You simply can't stay out of war. Fav civic comes too late and shared religion bonus isn't enough (quite big with Monte, but not enough).
Yesterday I rolled a random map and found myself isolated on a continent with Montezuma. I really did try to keep him quiet until oversea contact: adopted his religion, open borders, free techs, everything. No way. He declared 4 times until 1000AD, destroyed his stack on a hill/walls city every single time and signed peace every time after a couple turns, always giving me all his gold.
Then OB bonus gone, years of peace bonus gone. There is simply no way to avoid war with these guys. And it sucks, because they force you to build A LOT of units. Retired at 1200AD, still missing stuff like MC, construction, literature and generating less than 100 bpt.