I used to use KDE in the house and at uni. But it reminded me too much of Windows (the K menu especially). But I've also heard good things recently about KDE, even the chief himself (Linus Torvalds) prefers KDE over GNOME (can't remember source but it's pretty well known). However I may give a few others a bit of a try such as XFCE, Fluxbox, E17, etc because I probably wouldn't jump ship until KDE 4