You're Favorite MMO?

Hello! I don't know about y'all but I enjoy MMOs very much and I have put thousands of hours into these type of games. I was wondering what y'alls favorite MMO is. Mine is probably Runescape, one the most popular F2P MMOs out there (I'm pretty sure everybody has heard of Runescape before once in their life). Oh and yea did i mention its a browser game? You can also download a client for it as well if you don't like playing it on the browser. But anyway what is y'alls favorite MMO?