If I reviewed games I'd have trouble giving out 10's, just because I feel nothing is truly so flawless it can't be improved in some way (I'm an artist and my own work is never ever good enough for me, so I may just be a hardass).
But if I had to pick games I've played that were the least flawed from my perspective, I'd have to choose...
The Last of Us
Super Mario Galaxy
Mass Effect 2
I can't think of anything I dislike about those five.