gamers (you know the actual customers) won't give a rats behind ... but if you want to impress a C++ programmer you're not going to do it with BASIC.
Depends. I've worked with a fair amount of C++ programmers over the past few years, and most C++ programmers are fish out of water when they're expected to produce results in a rapid development environment. You can do whatever you want in just about any language now. It's a matter of calling the library that sits between the application and the driver where the real performance is leveraged. The playing field in terms of visuals is going to even out in the near future. Rapid development will be more important at that point. Successful utilizers of business software has already reached that point, and it's only a matter of time before the game industry adopts this same approach.
As you've mentioned above, the end result is what matters. Impressing a C++ programmer is a moot point. I'll probably get slammed for saying this, but in the companies I've worked for recently, they are a dying breed in the real world of development (Most crossing over to the .Net side). In these situations, you'll impress a C++ programmer far more if you have adopted proper software engineering skills and you can effectively apply them to whatever language you're using.
.Net is close to cross platform. Mono (http://www.mono-project.com/Main_Page) is slowly working toward it.
In my opinion, time would be better spent honing skills on design and game play studies than the syntax the game is developed in. Language will always be a moving target.