Societies was an abomination. Sim City Classic was fun, but given the other ones, I wouldn't be likely to play it. Sim City 2000 was one of my first ever games, and I had a world of fun with it. Sim City 3000 had the best music of the series, was probably the hardest, and extremely fun- it had the best advisors as well. Sim City 4 was eye-candy and fun to play- right now, I play Sim City 4 along with all of the downloaded music from Sim City 3000 (you can get it off the Sim City website).
However, right now, I think the future of the City Builder Genre is in the City Life/Cities XL series from Monte Cristo.