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.
@starbreaker yeah, they sure are! my in-laws gave this one to me for Christmas and I couldn't be happier with it.