This discussion is soooo old
The project I work on at my day job is *very* large scale. Some parts of it have hard real-time requirements and are basically written in C with classes. Some parts are C++ because they are compute-bound. But the majority of the components is written in C#, because performance simply isn't the top priority, productivity is.
Use the right tool for the job and be done with it.
Most developers I meet every day are entrenched in "their" world, but I love switching between the worlds and the languages. Spend the morning writing "fast" code, go to lunch and then switch over to writing "nice" code. What really annoys me though, is the fact that everyone and their dog calls themselves a "C# developer" nowadays after reading a few tutorials. It's sad to see so many programmers being completely oblivious of all the nice aspects of the "high level" languages that we willingly paid for by sacrificing performance.