Heavy Rain, God of War III, Final Fantasy XIII.

Now for next half I think it will be one of these:

Little Big Planet 2

Gran Turismo 5

Kingdom Hearts Birth by Sleep

And maybe Crysis 2/or Medal of Honor

Probably FFXIII (fun gameplay, brilliant cutscenes, and lengthy single player game). Strange pick but I liked it the most.

Heard good things about RDR and SMG2 but haven't played them yet. I imagine they're both in with a good shot of GOTY.

Played  Mass Effect 2 and God of War 3, both outstanding in some areas and very mediocre in others. I can't help but be a tinge disappointed with both given that I was massive fan of their predecessors (e.g. mass effect, and god of war 1 and 2).

PS3 - God of War 3.  The game is non-stop action from beginning to end.  Probably my favorite PS3 game to date.

Xbox 360 - Alan Wake.  Best atmoshpere and story so far this year.  This game also created some of the best suspense available in a videogame.  Really looking forward to see where the DLC takes the game.

Wii- Super Mario Galaxy 2.  The best platforming this generation and it's Mario...How can you go wrong.

What a first half of the year this has been for gamers.  What had been the post holiday drought in previous years, has turned into a flood of quality games.  There was a great game released in every genre, what more could you ask for?

- FF XIII

- God of War 3

- Red Dead Redemption

We are talking contenders right?

God of War III

Mass Effect 2

Red Dead Redemption

Super Mario Galaxy 2

Worthy Mentions are: Heavy Rain, Final Fantasy XIII, Battlefield Bad Company 2

Haven't played that many games lately and none really that aren't on PC/Wii/DS. So speaking partly from experience but mostly from what I've heard.

Almost certain to get some GotY:

Mass Effect 2: Perhaps not as fun as the first game, but just as epic and still completely amazing.

SMG2: This is gaming distilled. Nothing but pure blissful platforming.

Quite likely to get some GotY:

Red Dead: Heard only good things, might pick up a few GotY though there are some big contenders.

GoWIII - While not my taste in games, people who like it seem to love it =P

Unlikely but still possible:

FFXIII - Huge franchise, but was only received luke-warmly.

Heavy Rain - Heard good things, but not sure if it'll pick any up.

MHTri - From what I've heard it's more fun than what its been reviewed as. Since the GotY is retrospective it could pick some up from people who've been addicted to it for a few months =P

Of course there are some huge contenders arriving in the next half of the year.

Super Mario Galaxy 2

Monster Hunter 3

Mario Galaxy 2, Monster Hunter Tri, SMT Strange Journey, SSF4, Cave Story... it's been a pretty amazing 1st half so far.

well since i'm a completionist freak when it comes ot things i'm just LOVING Monster Hunter Tri, so that gets it for me so far

have only played like 3 levels in SMG2 so far so can't comment on that other than saying its awesome having yoshi and if as good as first galaxy will be great fun.  Though do have one complaint regarding galaxy, and its not the games fault but more the sytems.  From where I play the pointer is very often jumpy and sketchy, so I have to get a great experience in pointer i have to stand up.

Which makes me really excited about prospect of the new zelda no using the ir bar for pointing. 

You probably need to adjust the sensitivity for the pointer in the system settings menu.