Bleh, OP already (more or less) posted my list for me.

I'd add FFXIII, which I think recieves far more badmouthing than it deserves.

Nice Thread

I have a lot of underrated/undersold gems for this gen. Almost all my favorite games of this gen were really underrated. A couple of games comes in mind (in no specific order):

-Fragile Dreams Farewell Ruins to the Moon (Wii) : It's such an amazing experience, it doesn't have a deep battle system but it does have a certain atmosphere, it's a sad sad game. You need to experience this.

-Xenoblade (Wii) : Well this game got attention's but it deserves a lot of more sales. Some may think this game is overrated but it's really the best JRPG of this gen and maybe one of the greatest JRPG of all time.

-Child Of Eden (PS360) : This game was announced as a killer app for Kinect and was a flop. I can understand the reasons because this game is like 2hs long but it's a great game I only played in a friend house and man what an incredible game it is. Such an amazing experience.

-FF XIII : Yeah this game sold great but there is a lot of hate around this game for no reason. I understand most of the reason but it got a lot of more hate than it deserved. Overall it's a very good game

Endless Ocean is underrated, Xenoblade is undersold.

(Undersold)

Vanquish
Infamous 2
Motorstorm Apocalypse
Deus Ex HR
Top Spin 4
Modnation Racers
Castlevania LoS

I think 99% of the games are overrated, it's pathetic that the average score of all 360/PS3 games is ~72/73, which should mean a "good game".

I actually enjoy titles I would give a 7 to, like LA Noire, Darksiders oder Resistance 2.