Some people, for some reason, were disappointed with the last 3 or 4 main integer Final Fantasy games. Perhaps it's rose-tinted glasses or perhaps it's just changing trends within the industry, but these modern day games just don't seem as good as when we were kids.
To celebrate Final Fantasy's 25th anniversary (proceed to feel old), Square Enix are supposedly announcing the next game in the main series, Final Fantasy XV, at next year's E3. This is according to GamesMaster UK who also say that the game is in development for the PC and Wii U, as well as the 360 and PS3. This'll be the first time a Nintendo system sees the release of a non-spin-off Final Fantasy in over a decade and the very first time the PC is seeing anything other than an afterthought port outside of Final Fantasy XI.
Obviously this is very much a rumour, especially when you take into account which platforms it may end up on. For now post this firmly in the "possible" column.