Depending on the game it varies, perhaps your on an adventure to save the crystals in there shrines, maybe it's defeat the 4 elite monsters, defeat an emperor taking over and so on.
Final Fantasy VII, Final Fantasy VIII and Final Fantasy IX.
Final Fantasy XIV is supposed to come out sometime in 2010 (in Japan, at least)
PSP Final Fantasy Games:Crisis Core: Final Fantasy VIIDissidia: Final FantasyFinal Fantasy IIFinal Fantasy: Tactics
Final Fantasy X-7? no. there is Final Fantasy 10-2 which is the sequel to Final Fantasy 10 (and is the only actual sequel in all of the final fantasy games) and there is Final Fantasy 7, but there is no Final Fantasy x-7. the games may be made by the same people but do not relate to each other in anyway other then the fact they are Final Fantasy.
You can play as characters from multiple final fantasy games (though not all) in games such as final fantasy dissidia 012: duodecim.
There aren't any Mario games with final fantasy characters.
Sin was only in Final Fantasy X, and mentioned in Final Fantasy X-2.
There are 3 final fantasy in a playstation 2 console, Final fantasy X Final fantays X-2 And Final Fantasy 12
There is Final Fantasy XIII and Final Fantasy XI for Xbox, but no games have been announced with Kinect support.
Final Fantasy games revolve around story, so if you're good at English, then yes. I'd say Final Fantasy is right for you.
Final fantasy X, X-2, and XII
The newest Final Fantasy VII game is Crisis Core: Final Fantasy VII for the PSP.