Ubuntu 14.04 Trusty Tahr Released

- http://xubuntu.org/getxubuntu/
- http://www.kubuntu.org/getkubuntu
- http://lubuntu.net/
- http://www.ubuntu.com/download/server
Although critics often disparage the animal codename, the uniqueness of the word does aide Internet searches. For example, if you search for "Ubuntu Bluetooth" you may get outdated information from previous versions that is no longer relevant. However, adding "Precise Pangolin" or "Trusty Tahr" really helps narrow down the results.
Apart from that, here are some thoughts: Mint has some weird update strategy that some called less secure than Ubuntu. I would certainly pick Ubuntu 14.04 LTS right now because you don't have to care about anything for 5 years update wise. You can install KDE, Gnome, Mate, Xfce or whatever else you like on top of that base system. Whatever distro you chose in the end, I'd also stay with a Debian base, it's well supported and documented and now even Valve deploys Steam on it which might get students more interested.