Good casual gaming laptops?

I don't know anything when it comes to the software of computers but I'm looking to get a new laptop and want to use it to play my videogames. I usually play on my xbox 360 or PS3 but I don't play online anymore so I wanted to get a decent laptop for around $1500, preferably a bit less, just to play RPG's like Borderlands, Skyrim, Dishonored, etc. I don't need the best graphics in the world, just a computer that can play them decently. Originally I was going to get a MacBook Air or an Asus zenbook prime ux31a b/c I wanted an ultrabook. I know they weren't meant for gaming but would they be able to run the games with a decent FPS and decent graphics? If not what would you suggest?

[I know I would need to run Boot camp on OSX to run PC games]