The thing with Go is, it's really easy to write your critical path in C and then write the other 95% of the code in Go and not have to deal with crap like null-terminated strings and a lack of built-in data structures.
Go has better integration with C than any other language I've seen.
Ok, not better than C++ and I haven't used D. I should've said "other mid-to-high-level langauge". But using C++ doesn't solve my complaints about the clunkiness of the non-critical path stuff. Still have wacky string handling and I'd rather write my own bintree or hashmap than have to use STL.
In fact I don't, which was why I said "critical path in C, rest in Go". Usually I do Java but if I need to use C, I'd like to just write the part that needs to be fast, then drive it using something else. Python is also acceptable when it comes to parsing command line options and the like, and it's as slow as dogshit.
"Lots of free time" would be dicking around with cryptic STL error messages.
Go has better integration with C than any other language I've seen.