Length wise Final Fantasy, being I like 4,5,6,7,9,10. For shorter series I like Assassin's Creed, Mass Effect, Bioshock, Star Ocean. Stand alone games only Chrono Trigger comes to mind(screw Chrono Cross, that game can burn in hell.)
Why I do believe you have just out done yourself, my good sir! You have earned yourself a gold star! Oooh... Shiny...The Real Sandman said:Hmmm...
Ratchet and Clank
Saints Row
Theif
Devil May Cry
Serious Sam
No More Heroes
Assassin's Creed
F-Zero
S.T.A.L.K.E.R.
Duke Nukem
Prince of Persia
Star Wars: Dark Forces / Rouge Squadron
Gears of War
Siilent Hill
Yakuza
Fallout
Wario-Ware
The Sims
Condemned
Shenmu
God of War
Monster Hunter
Left 4 Dead
Super Smash Bros.
Just to name a few...