Very useful info, thanks Mark! Just one final question, it might be a supid one, so be warned.

Is there a way to install *both* desktop environments, and then switch easily between then? Like booting into text modus, and then type 'startkde' for the KDE environment, and 'startgnome' for the GNOME environment? (I'm just saying something)

That way I could easily try them both out, and see which one I like best. (even though the final idea is to also learn the console commands and learn what makes a Linux system tick... I really would like to be able to control my PC again like I did in the good old days of DOS. Eventhough I know Linux is not comparable to DOS, but you get my point. )