Benjamin,

   I don't believe Gears of War was done in C#.

   If you want to do game development in .NET, check out the XNA kit.  It
will allow you to create games for the XBOX 360, and I believe, the windows
platform.

You've asked a very complicated question.  I'm not going to offer a very  
complicated answer.  :)

That said, there's nothing fundamental about C# that would preclude coding  
a 3D shooter (for example) in that language.  I think the biggest issue  
would be the non-deterministic memory management, which could lead to  
frame rate stuttering.  But I think that there are techniques one could  
use to minimize the issue, if not eliminate it altogether.

The other question is whether you can get at DirectX via C#.  The short  
answer is that you can.  For example, XNA provides this if I recall  
correctly.  Last I heard, you needed to use an Express version of Visual  
Studio to use XNA, and that could be a bit of a barrier.  But for all I  
know, that's no longer true, and in any case I think that's more of an  
arbitrary limitation Microsoft imposted than something fundamental about  
the language.

I think that the biggest reasons games are mostly coded in C/C++ is just  
inertia and support.  That's how those kinds of games have been written  
for a long time and so people are used to doing it that way.  Not only  
does it make sense to stick with the code base you've already got just  
from a practical point of view (why rewrite something that already  
works?), it's probably easier to get experienced help and pre-packaged  
libraries to help with game development if you do that.

I'd say that if you're interested in both C# and game development, you  
should definitely check out XNA.  If there's a reasonable way to write  
games in C#, I'd guess that's the most likely candidate at the moment.  :)

Pete

For simple to intermediate games then C# would be an excellent choice.

I believe there game toolkits available.

For the most advanced games, then I think they will continue to
use C/C++.

The usage of C/C++ is to some extent historic determined. But
the real advanced games some of the parts especially for graphics
needs to be highly optimized for the hardware. I guess you
could use a mix of safe C#, unsafe C# and C/C++. But there
are not much point - if safe C# does not fit the task, then
doing it all in C/C++ is simpler.

Arne

Thank you very much for your replies!