MOST AMBITIOUS - ULTIMA ONLINE . Tried to have a working ecology, employed a constantly mutating skill system instead of a linear level progession, a host of player housing and shop options from launch, non violent professions, etc., etc. Sure, it was all completely broken, but you have to admire the effort.
MOST ADDICTIVE - EVERQUEST . Not only was it designed to be psychologically addictive from the ground up with its slot-machine styled randomness, but its punitive difficulty on release made the tinest victory a tremendous rush. Less draconian titles have helped make the genre accessible to more than just clinical masochists, but the MMO experience has lost something essential in the translation.
MOST POLISHED - WORLD OF WARCRAFT . The penultimate MMO experience, built upon the bones of its vanquished foes. Accessible as hell, and polished to a blinding sheen in the best Blizzard tradition, WoW's imagination-beggaring success renders its lofty perch atop the MMO hierarchy inviolate. In making the game playable and enjoyable by all, however, they have drummed away most of the challenge and intrigue. It is now not unlike a colorful chat room with orcs.