Borneo.
Watch it from the beginning and be a real fan. A REAL FAN I TELL YOU!
jk but seriously me deciding to watch survivor in order was the best decision I ever made
Micronesia starts off incredibly slow and has a horrible ending. It's fun towards the end, but it starts lame and ends terribly.
Borneo is a great one but only if you watch it first or early. People who think it sucks just can't appreciate that it was a different show -- which is the problem you have if you start with something like Micronesia.