There are so many MMOs out there with different genres, different mechanics, different approaches to play, play-style, classes, missions and more. Sometimes we're asked to assemble short lists of the 'best' MMOs out there.
There isn't of course, really a notion of a 'best' one, as the criteria we all use to grade them on are very subjective. Everyone's got their likes and dislikes from camera controls and inventory management, to raids and PvP/PvE, even mission-styles, setting and story. We've also each got different priorities that make those aspects more or less important to us. We all have some ideas in common, however. So, tell us - what do you think makes a good MMO? What particular things stand out or really grab you in a game? What do you really miss when it isn't there?