Debian 9 stable Xfce running on my new (to me) used Lenovo Thinkpad T-420. If you are a student or are looking for a good cheap laptop check one out. I had an issue getting an extra HD that fit. I needed an extra slim HD, which Best Buy didn't have and couldn't order, so I went with an SSD. Dealing with the UEFI was a simple matter in set up. I really like the keyboard. Its fast, too. Overall it blows my Asus eeePC away, even though they're the same age.
@ewankeep I have a used T430S running OpenBSD that I carry everywhere. T-series ThinkPads are excellent little computers when you can buy them used.
@starbreaker @ewankeep Home is a T520, spare is a T420, and work is a T430s. I'm really hoping I can keep/buy my work laptop when I leave (it's pretty banged up after 5 years tbh) because it is the best damn laptop I have ever owned (in particular the keyboard layout.)
@starbreaker yeah, they sure are! my in-laws gave this one to me for Christmas and I couldn't be happier with it.