A ton of games. Link's Awakening the most, though.

I don't have that habit of playing more than one time. The exceptions are:

Kirby's Dream Land (gb)- too many to count
Resident Evil 4 - 2x
World of Illusion (Megadrive/Genesis) - 7x+
Luigi's Mansion - 2x

Metroid:Prime 5 times. My favourite game ever. I'm itching for an HD remake
Metal Gear Solid 1,2,4 several times each.
Demon's Souls 3 times

There are others (Uncharted etc.), but I'm only proud of the obove ones.

Some games are just comforting to play. Their like a familiar friend that never lets you down.

I played all of the Ratchet & Clank games obsessively... Meaning I couldn't tell you exactly how many times, but definitely more than ten. Each. Except the PSP ones. Only Size Matters has that honour.

KOTOR has been another one, with me trying the different class types and light/dark side... and just playing it again because it's awesome.

Another would be the Assassin's Creed franchise. I've played through the first one three or four times and II/Brotherhood around five each (haven't gotten Revelations quite yet).

And lastly, the R/B and G/S Pokemon games. I've spent at least a couple hundred hours on each set at the very least. I'd buy all three (R/B/Y and G/S/C) and then make one of them my uber awesome team of murder that I kept forever, and I would use the other two to trade (with myself between GBC and GBA, go me!) and just play through the games again. Looking back, I still don't feel silly for buying what is almost the exact same game three different times. No regrets!

I'm going to have to list almost all games I've played during my life if I want to reply to this thread... and I'm going to forget a lot of games too. I'm actually surprised that a lot of people in this thread only have a few games they have replayed more than once.

I'm only going to list the games from this gen:

PS3

Metal Gear Solid 4: Guns of the Patriots - 14 times
God of War III - about 8 times
Final Fantasy XIII - only once, lol
Nier - about 7 times
Bayonetta - about 7 times
Yakuza 3 - around 3 times
Vanquish - around 4 times
Castlevania: Lords of Shadow - around 3 times
Resonance of Fate - only twice
Shadows of the Damned - 5 times
Resident Evil 5: Gold Edition - 4 times I think
Heavy rain - twice by starting all over again from the beginning and who knows how many times by selecting chapters.


PC:

The Last Remnant - only twice
Silent Hill Homecoming - like 3 times
Devil May Cry 4 - like 9 times only by starting all over again from the beginning but I played it over 110 hours by selecting specific missions I liked to play.
Resident Evil 5 - like 3 times

Hmm... I don't remember what else I had on PC :S

Anyways, if there are some games I like to go back to and finish them again even though they're old and from last gen they're Devil May Cry 3 and God Hand... damn, I never get tired of playing those two :P