They kind of recanted that statement and said they meant it for "web servers" and stuff like that. However I know there has been at least a window manager made in Go.

I don't think it's the best fit, but it's a lot better than many current solutions. I personally prefer Haskell for anything others would write in Go, however many may find Ocaml or Erlang to fit them better.

However I'm biased and believe that functional programming is a better fit, more bug-free, easier, and simpler for most use cases than imperative programming.