Favourite Game

So here's a question that will get some debate going. What is your favourite game you have ever played and why? As I'm writing this I realise how difficult a question this can be to answer. Right now I'm thinking of Grand Theft Auto (Vice City or IV), Knights of the Old Republic, a plethera of Championship and Football Manager games or something as left field as the original Rollercoaster Tycoon.

However I think I'm going to have to go with the original Call of Duty game. Although the WW2 FPS was pretty saturated at this point Infinity Ward managed to come up with something comletely new and so engaging to play. At the time I don't think anyone would have predicted that Cod would have taken over the way it did but looking back should we not have seen this coming?

Knights of the old republic 2 for me, epic game still play it now.

All the usual cliché's, as well as a few others, that I'd call favorites. In no particular order;

Final Fantasy VII
Final Fantasy X
Final Fantasy XI
Minecraft
Counter Strike: Source
LoZ: Ocarina of Time
Metal Gear Solid
Pokemon Gold/Silver
Goldeneye 64
Skate
F Zero X
Metroid Prime
Command & Conquer: Red Alert
Gran Turismo 3

Hasn't really been anything in the last generation or so that I'd consider other than Skate, maybe the first Gears of War for how good it was online (And finally getting my 'Seriously...' achievement >_>) I spent a lot of time on KotOR I/II, the early THPS games and Pikmin as a teenager, too.

I could probably add Faster Than Light too, that game is addictive, but crazy hard.

EDIT

I could probably fill the list with just stuff from the N64, actually.

Bf3
F1 championship addition
Cod waw
Hot wheels stunt track challenge. ( I think that's what it's called )
Gran turismo 5
Gran turismo 4
Bf4 (when it comes out )
F1 2013 (when it comes out )

hmm lets see, got a few!

Civilization (PC)
GTA
Saints Row
Fallout New Vegas
Skyrim

... just a few of the top of my head, probably loads I've missed out

medal of honor frontline for ps2 just amazing game what else is there to say