Siam. In a current game I'm playing, it was me at one end of pangea, and japan at the other end. Siam was the civ just west of Japan. He(Siam) destroyed bismarck, monty, and is well on his way to destroying Oda.
At my end, I have already took out the Arabs, Indians and Rome is down to 3 Cities, and paying me luxuries and gold per turn. Seems the next viable thing to do is wait until Siam destroys, then coast out and win scientifically or by culture or conquest, since I lead in all 3.
I just don't know If I can stand the longer turn times that come with late game though, so I'll probably lay down the hammer and mess some dudes up.