I wonder if Go will be similar to Scala where it arrives to solve issues with Java (or C++). I found that although Scala is a nice language in many ways, the smallness of the community prevented me from adopting it big time for most work. The same holds true for languages like F#. They're fine for special cases (likely what Google intended with Go), but won't be a general purpose replacement for more mainstream languages without some huge advance in support (like what the Rails team did for the Ruby language).

Just my humble opinion..