Best? I wouldn't exactly call these the best but I could recommend a couple of solid/fun titles that probably got overlooked by some people.
Binary Domain Singularity Dark Sector
Binary Domain is probably the best of those 3. Those last 2 may be hard to look at now. Been a while since I've played them. But as old as they are, this would be a great time to check them out. Metro 2033 definitely warrants a try.
As far as "best" goes, Red Dead Redemption is definitely high on my list. To be honest I'm having a hard time thinking of many exclusives that most people wouldn't have already tried.
The 360 does have a couple of amazing arcade games. Shadow Complex is awesome. Mark of the Ninja is quite good. I'm having fun with State of Decay.
Playing: The Last of Us, Borderlands 2(PS3), BioShock Infinite, State of Decay Wants: The Bureau: XCOM Declassified, HL3, a PS4