It sounds like you want an ultra book. Probably either the Asus UX31 or the Macbook Air, they both have nearly identical processors and very similar cosmetic design and they're also basically the same price. I would suggest getting the one that has better support for the programs/games you'll want to use as the only real difference between those two is windows vs osx.
The thinkpad x220 is also a great laptop in the same price range with the same processors as those other two ultrabooks. It is in the same size/weight range also but cosmetically it's more subtle than the other two (not as shiny). If you already like lenovo products than it might be the best option if you know you want windows.
