SSX 7th gen
Catherine
Crash Team Racing
RE4
Civilization

There are loads if you include racing/fighting/competitive multiplayer... they are all (as good as) infinitely playable.

If I limit it to single player narrative driven games, then the ones I have replayed the most are:
Goldeneye (N64)
LoZ: Windwaker (GC)
TimeSplitters 2 (GC)
Battalion Wars II (Wii)
Resident Evil 4 (Wii)
Half-Life 2 + ep1&2 (PC)
GTA:Vice City (PS2 & PC)

For me it's always RPGS, Final Fantasy and Suikoden and the main franchises I've replayed alot.

 Smash Bros Melee, Mario Kart DS, Mario Kart 8, Wind Waker HD, A Link to the Past, Super Mario 64/DS, Final Fantasy IX, Left 4 Dead 2 and MANY other games! I could probably spend DAYS listing games I consider to be "replayable"!

I've always been fond of Dead Rising considering how much replayability the franchise allows. Heck, it is even encouraged that you played more than once, trying different times each time.

For the same reason, I think musou games also have nice replayability.

Other games include RPGs (Both JRPG and WRPG), first/third-person shooter games with solid content (Gears of War comes to mind, it is always nice to play Horde Mode with a friend), fighting games such as Smash Bros, Tekken or such, and timeless games that put joy into motion; examples I can think are Dead Nation or Geometry Wars 2 (That game about a Knight and a Witch on 3DS as well).

Parasite Eve 2
FFX/IX
Souls games
TLOU MP
MRM
...all those that comes to mind...

Mario Kart 8
Pokemon X and Y
Kid Icarus Uprising
Fifa anyone that has ultimate team
Skyrim
Animal Crossing

and of course... SMASH BROS.

Stronghold 1 & 2.
GTA Vice City.
Red Dead Redemption.
Uncharted 3 multiplayer.
Mafia The City of Lost Heaven.

Xenogears
Star Ocean: The 2nd Story
Legend of Dragoon
.Hack G.U. series
Zone of the Enders: 2nd Runner
Grand Theft Auto: San Andreas
Shadow of the Colossus
Gunstar Heroes
Teenage Mutant Ninja Turtles: Turtles in Time
Spider-Man 2
Uncharted 2
Final Fantasy 9
Heavy Rain

Uncharted, Infamous, Batman Arkham series, Puppeteer, Heavy Rain, Beyond 2 Souls, Ratchet and Clank (excluding FFA and A4O), God of War (excluding CoO for me), Sly Cooper, Jak and Daxter, Resistance 3, MGS3 and 4, 3d Mario, Star Fox 64, Mario Kart, Smash Bros, Crash 3. All of these are part of my permanent collection because I only keep games that I know I'll wanna go back and replay at some point lol