If you plan on getting a career in the game industry, C++ is a must. This is based on the many "help wanted" requirements I have read for various companies.
The way MS is going C# will be very important for game writing in relatively near future. I would not stick to C++ 100% if I plan to create AAA games for years to come. Luckily I don't have to program for living anymore but if I do I'd make sure C# was high on my priorities list.
Barney