by cross-platform I mainly intend Windows and Debian, I do not need a GUI. I need to elaborate text, write/edit files. Programs may need to accept command-line arguments and in some cases prompt for user interaction (input) some programs may need to access an internet connection and send/receive data.
It would be a plus if I could make it use web services written in .net Im not worried about the learning curve however the more simple the better.
Another plus would be the ability to create/interact with databases, possibly using common SQL strings, but I'm open minded.