It's still there, it's just Windows that became boring. Take the most plain Ubuntu system and looking for "window manager" - there are dozens of hits! Install

It's still there, it's just Windows that became boring. Take the most plain Ubuntu system and looking for "window manager" - there are dozens of hits! Install "wmaker" for that classical look and spend a few hours picking up the set of dockapps you like. Try a dynamic tiling manager and a static one.