For a long time I've been using a very minimal environment on Linux. That means no desktop environment, just a minimal window manager (it was OpenBox) and a simple terminal (rxvt-unicode). For more than 10 years I didn't even had a graphical file explorer installed on my system.
Approximately one year ago (maybe a bit more) I became curious of the Linux experience for "muggles". How could I recommend a system that I wasn't actually using? I spent a bit of time on the web to decide which desktop environment I would try and on the paper KDE looked the best.
So I did a clean install of Debian choosing KDE at install time (instead of… well, nothing, as I ever did before ^^). I'm really impressed with the quality of the environment and of the base apps. Except for the PIM suite, which looked really good on the paper but which was an unpleasant experience. I switch to Thunderbird and I'm very happy with it (before switching to KDE, I read my email in Emacs and has no proper calendar apps apart from a custom shell script which managed text files…).
Kool Desktop Environment.