What is the ideal platform for developing the most flexible web application possible? I want it to run on Windows, linux, and Mac OSX, and it will need to support sophisticated graphics and database access. I presently develop in .net, but I'm not sure that it offers the graphics support that I need across most platforms. Is that an incorrect assumption? If I'm wrong there then .net will probably be my choice, but right now it seems as though java or something else would be a better option. Of course, if it's 'something else' please tell me what you'd recommend since I'm obviously not familiar with it.
Please just tell me the best way to do this, without worrying that I'm familiar with .net. If it's not the best choice then I'll learn a new language. I learned to program with C and C++ so java or something else won't be a problem.