Help me find a new Laptop for my girlfriend

So another year is almost over and my girlfriends' laptop is just... well... an old and heavy piece of junk. It's an abhorrent thing to most PC enthusiasts really. This year, I'd really like to get her a thin & light notebook that really shines. I'm certain that we can do this without going far beyond the $600 mark, but it's been so long since I've used a PC that I haven't kept up with the models and I have no idea where to start. She's going to be using it mostly for reading, writing, and creating documents; along with the standard youtube, web browsing, Netflix, and etc. that you'd expect.

The list of requirements isn't long at all, but I'm fairly certain it should:

* Be Thin & Light (13 inches)

* Have Quality Materials & Construction

* Have a Good Display

* Have a Good Keyboard & Trackpad

At the most basic level this needs to be - and I'm really sorry for using this example - as good as the MacBook Air. She likes using Windows so I've decided we need to go that route as far as I'm concerned. The reason for requesting a solid construction with good materials (like aluminum) is that it's going to be thrown in her backpack for a lot of commuting and it would be good if it could take a bit of punishment here and there.

Thanks everyone in advance for your help! So far I've looked at a couple of different brands like Asus, Acer, and HP, but nothing has popped out at me yet.

(and no Chromebooks - our University uses proprietary Windows software)