Choosing an ultrabook for study?

Question

laptops

Good day.
It so happened that I was leaving to study in another city. The question arises of buying an ultrabook, and powerful enough not to need a PC, since I won’t have a PC for the next 4 years, and I won’t require the purchase of a new device for at least a couple of years. But at the same time quite light (< 1.5 kg) as I will most likely carry it with me a lot. Needed for studying at a technical university, the Internet, possibly games, etc.
So, you need a fairly light and productive laptop, preferably within 40-50k, and it is possible to bring it from America.
Ps I do not understand the win8 philosophy and if I have a windows laptop, it will be a seven.
So far, the eyes fell on:
Apple MacBook Air 13.3-Inch Laptop
Apple MacBook Pro 13.3-Inch Laptop with Retina Display
Samsung ATIV Book 9 Plus 13.3-Inch
ASUS Zenbook UX32VD 13.3-Inch Laptop

Answer 1

If possible, take a Mac. In my technical university, software was used mainly under Windows. Various programs for laboratory work. I just installed a second system on Mac Windu to solve this unpleasant problem.

Answer 2

Samsungs are awesome, but only under Windows. And the battery doesn't last long. This asus is not even worth looking at.
Take mb pro retina or air. Necessarily with ssd and 8-16 GiB Ram, otherwise you will soon be thrown into the trash (I'm not sure that in '2014 the memory changes by hand).
From myself I can advise Thinkpad X240, t440s.