Let's say you have a company running a lot of C/C++, and you want to start planning migration to new technologies so you don't end up like COBOL companies 15 years ago.
For now, C/C++ runs more than fine and there is plenty dev on the market for it.
But you want to start thinking about it now, because given the huge running code base and the data sensitivity, you feel it can take 5-10 years to move to the next step without overloading the budget and the dev teams.
You have heard about D, starting to be quite mature, and Go, promising to be quite popular.
What would be your choice and why?
D and Go will probably just become as popular as Python and Ruby are today. They each fill a niche, and even though D was supposed to be a full-fledged replacement of C++, it probably will never acquire enough mass to push C++ away. Not to mention that they both aren't stable/mature enough, and it's unknown whether you'll have support for these languages in 10-20 years for the then-current hardware and operating systems. Considering that C/C++ is pretty much the compiled language and is used in the great majority of operating systems and native-code applications, it's very unlikely that it'll go away in the foreseeable future.