I've never played MGS or a main FF game.

I only played renevant wings for the DS derp.

Pokemon
Mario
Metroid

Metal Gear Solid
Killzone
Little Big Planet

Looking at the top game sales on vgchartz, mostly icky casual games; Wii Fit, Just Dance, Brain Age, that Kinect one..

The highest placed real game series that I haven't played is Kingdom Hearts

I haven't played Metal Gear Solid.  Seems so complex that I'm not sure I can just jump in.  I've played older Call of Duty games but not the newer titles: no Modern Warfare or Black Ops--though I actually own one, I just can't find the desire to put the disc in.  Never played Diablo or Starcraft.  Never played Hitman or Max Payne.

There are a LOT of franchises I've only played a few minutes of, though, enough to decide I didn't really care for it all that much.

Metroid Series
Hitman
Far Cry

Call of Duty! *gasp!*

Anything on an Xbox. I have never played anything on one, nor will I.

Pokemon
Fable
Elder Scrolls

I've only played COD twice in my life, only played Halo once. Haven't played Pokemon since the Gold and Silver versions. Have never played Gears of War. I really don't like playing super mainstream games, it makes me feel so ordinary.

Gears of War and God of War. Those series just never interested me at all.