The biggest and the best rpg Final Fantasy's developer Sqare Enix are making an mmorpg for the PS3.They will then port it to PC cause they don't know if mmo's will be popular on a console and want to be on the safe side.They haven't announced the release date yet but they say it will be after Final Fantasy 13 during 2009 holiday season or early 2010
http://www.gamespot.com/ps3/rpg/untitledsquareenixnextgenmmorpg/index.html
http://www.gamespot.com/news/6147946.html?tag=other-user-related-content;4
http://www.gamespot.com/news/6154196.html?tag=other-user-related-content;2
They are not developing a sequel to FFXI but an whole new mmorpg