Fairly Easy.
1) Final Fantasy (Easily)
2) Deus Ex (Not Easily As it only has two games which I Find both Excellent, and the DE1 only surpassed by 2 of what I said was 2 FF games)
3) Metal Gear Solid (2 Extremely Top Knotch Ones, (1 2), followed by many great ones)
And Mario would be the franchise, I'd replace with Deus Ex, if 2 games can't count as a franchise as FF-Fan was talking about. I don't find most of the games in the Mario series phenomenol like many people here. But for the most part they are always enjoyable, with a few masterpieces sprinkled in. And the franchise that's most fun with friends, Mario Cart, Party, Old NES ones where you switch everytime you die. The new 2D ones.