[fiatmoney]

Situations where you want a modern, strongly-typed language with easy C bindings.

IO-heavy operations, especially where it's primarily IO bound but there is a decent computational aspect (eg, working with an embedded database or doing lots of flatfile munging).

I've found the place where Go crashes and burns is if you're trying to implement / use lots of sophisticated custom data structures. It really really wants you to use the builtins, and the lack of generics is irksome.