I play all regions, that's why I list Half Minute hero as I've skipped the US release last year.
1: Dead Rising 2: Not the most polished game ever, but definitely the most fun I've had this year and I like it even better than DR1, which I adore. It's just one of those games that click with me and subsequently I love everything about it, warts and all. The locations, while not radically different from DR1 are so lovingly designed, I just love wasting time in the world and looking for secrets and other fun stuff. The combo system is genius as well.
2: Mario Galaxy 2: pure, platforming perfection. I don't need to tell you guys why this game rocks.
3: Mass Effect 2: Huge improvement over ME1, a lot of rpg elements have been removed, making it more of a shooter, but in this rare case it works. Great story and characters too, I'm not used to that in games nowadays.
4: NieR: Along with Deadly Premonition probably the biggest surprise for me. Very inetersting story, fantastic music, fast-paced and a great mix of genres. Not everything works of course, the side-quests especially are a bore, but all in all a very exciting and fresh game.
5: Alan Wake: I was always looking forward to this game ever since it was first announced, of course the final product is nothing like it was originally envisioned, but I like it a lot. The environments are linear, but pretty big at the same time, not giving you the feeling you're being led on. That and I love finding stuff and Alan Wake has a bevy of collectables and the story was pretty good.
6: Deadly Premonition: everyone knows this game is outdated in almost everything, but this is another rare case in where this actually works in its advantage. The Dreamcast-era graphics, wooden controls and all, it feels like a fantastically cheesy b-movie. The characters are genuinely great too, especially Agent York.
7: Amnesia: it's a short game, it's an easy game, it's a terrifying game. Truly and utterly terrifying. A true must-play for horror fans.
8: Half Minute Hero: While I'm not so fond of the other games on the disc, the Half-Minute Hero portion is absolute genius, it feels like a full, epic rpg, but very fresh. It's got humor, it's got a very fun plot, some great music and it pays homage to a time when these kind of high quality rpg's were released left and right.
9: Trauma Team: This is what I always wanted Trauma Centre to be. It's got an overly dramatic plot, but it fits the style, the characters work perfectly in this context as well and all the mini games are fantastic, the forensics and diagnostics parts expecially work wonders. It does regress into "combine whatever to see what works" territory a bit too often and endoscopy is kinda...crap, but on the whole there is something to love for everyone in this.
10: Donkey Kong Country Returns: I hate the Donkey kong Country series...there I've said it (I've actually always said this). I think they're charmless, overrated platformers. DCKR is great. It does rely a bit too much on trial and error gameplay, but the leveldesigns make up for this. You're constantly being confronted with new challenges and there's a shit-ton to do making this the 2d platformer of the year.
Honorable Mentions:
Heavy Rain
Fable 3
Ys Seven
Fallout New Vegas
Red Dead Redemption
Two Worlds II
Professor Layton and the Unwound Future
Lego Harry Potte
Kirby's Epic Yarn
Halo Reach
Most disappointing:
Dragon Quest IX: A pretty great game, but it kinda plays like Dragon Quest VII, which suffers from the same "problems". I just hate going to a town and solving its problem and then moving on to the next town and doing it again and again, it just got boring after about 40 hours (around the time I completely lost interest in the game).
FFXIII: I knew I wasn't gonna like it, but damn...this sucks. If there's one thing I hate it's playing an rpg that tells you what to do...ALL THE TIME. It's significantly worsened by the fact that this is feels like one long tunnel. When you do get past the horrible tutorial (which is 25 hours long...yes, really) the game does get a lot better and opens up a lot. Here, the game starts to feel like FFXII, which was brilliant. I've spent the majority of my 65 hours playing the game in Gran Pulse, but after about 30 hours, that really starts to gets annoying and boring as well. Also having boring-ass characters (fuck you Vanille, you may be hot as hell, but goddamn shut the fuck up!!) and a ridiculously convoluted story. So even though I wasn't expecting much, this is still Final Fantasy, I want it to be good so it still managed to disappoint me enormously. I dislike FFX as well, but at least there was a game to be played there.
Metroid Other M: God, don't get me started on this pile of crap. I don't want to use the word "rape" lightly, but they've effectively raped Samus. An unbelievably stupid story and pointless characters just add insult to injury. There's actually a decent game behind it all, but in this case the way the story and characters are handled is just too much. Whenever Samus started to talk I wanted to choke her. The level of retardation is pretty unbelievable. I hope Retro will return to the Metroid series and maybe also make it 2d like they've succesfully done with Donkey Kong. I actually do like the tech of the game, but the linearity kills anything decent they could do with it.