Another +1 for KISS, it's such an amazing launcher. I'm actually surprised to see it mentionned so much in this thread.
I have my 5 most used app on top of the search bar and my most used apps (that get automatically sorted by usage) readily accessible. The search feature + tags is so powerful, there's no need to scroll through the apps anymore when looking for something.
The X in XFCE doesn't stand for X11.
The name Xfce originally stood for “XForms Common Environment”, but since then Xfce has been rewritten twice and doesn't use the XForms toolkit anymore. The name survived, but it is no longer capitalized as “XFCE” and is no longer an abbreviation for anything (wiki)