I just bought an Acer C720 chromebook as a second machine and am absolutely blown away by how nice it is for $200. You can run Ubuntu (with your choice of wind

I just bought an Acer C720 chromebook as a second machine and am absolutely blown away by how nice it is for $200. You can run Ubuntu (with your choice of window manager) side by side ChromeOS with crouton, or completely replace ChromeOS with chrubuntu. There are some quirks if you try to replace ChromeOS, so IMHO stick with crouton and either xfce or unity. The screen is low end, and the track pad nothing to write home about, but the battery life and portability are unbelievable--a true 8 hours of usage in a machine about 2.5 lbs. heavy. ChromeOS itself isn't bad for just using as a browser and then crouton to fill in the gaps of missing stuff like a good text editor, development tools, etc. Even with just the basic 2GB memory and 16gb SSD version I have no issues with memory or disk space (about 8gb free once a basic ubuntu + unity install is added). I really can't say enough good things about this setup. I wouldn't use it exclusively as my only machine since 11" is kind of small, but as a second machine for portability or browsing the web it is fantastic.