My gut says Last of Us is probably a better game based on other Naughty Dog games. however, as i have still not played it and not gonna play it before the deadline i can't vote for it.
Arkham Asylum was an excellent game that I sunk many many hours into. I am sure i got extra DLC levels and completed nearly all the challenges. The combat felt really good, shame the ending was a bit crap.
Arkham Asylum
Tip for next time: make the whole thing a bit shorter. I lived in a different country when this vote started!!!
rp2000