ElmoFromOK not a muppet

Much to my vast shock, I was lucky enough to receive a PlayStation 3 for Christmas this year. I have long been an Xbox guy and have never really been a PlayStation guy. I think this is similar to being either a Marvel guy or a DC guy, for all you comic book fans out there*. Once you get into one camp, you tend to stay there.

So now I find myself in the PlayStation camp, and to be honest, a bit lost.  I want to start experiencing some of the great games that I have missed out on being in the Xbox camp for so long but have not a clue where to start.

So I ask you internet friends, what are the PlayStation games that I MUST play? Leave me a comment and let me know. If possible, let me know WHY you think I should try the game out. I would love to hear about what you loved about it.

^{* I am a Marvel guy btw, if you care. Although, I read indie stuff almost exclusively now.I just find myself board with the soap opera storylines of the mainstream comics.}