I have an Asus X205TA that I got a couple years ago on Black Friday for $150. It only weighs 1.5 lbs which is lighter than a Microsoft Surface Pro of the same size BEFORE you even add on the weight of the Surface keyboard. I carry it everywhere because it's so light that it feels like a paperback book. It has a 11.6" screen and 32GB SSD HD which is fine for Windows, Linux, and a few apps. No personal files, as they are all in the cloud. It's a cheap backup laptop that can handle all your office productivity needs in a pinch.

Also, for weekend getaways I often don't feel like carrying my work laptop around so I just throw this in my weekend bag and use it for work and web surfing. If it breaks or gets stolen (which is more likely during weekend getaways than during the week when you're on business), no big deal because it's so cheap. Plus like I said earlier, put all your files in the cloud so none of your personal information is compromised if your backup is stolen.

EDIT: I noticed they have since released a new Vivobook which is the same 11.6" size, but offers a faster processor and double the RAM and it still costs only $199. I'd get this one if my X205TA broke or got stolen.