A distribution of Linux that is nevertheless free, and the best of both worlds running from Windows and OS X. Easy for basic tasks, but gets EXTREMELY difficult to master in terms of installing certain drivers, and because quite a bit of the OS has to be done by command line. Very little software that is completely useful, and the software that are useful, require a lot of skill to master, and eventually ends in anxiety attacks, but, given time and community support, should get you where you want to go.
" Oh look - Ubuntu I can write e-mails, browse the web, do more things, listen to media edit media, better than other OSes... Wait, WTF? Command line? WTF is Sudo/etc/gedit86, what do I do now?"