Open-Source Language and GUI Choices

[projess]

I am beginning to transition everything from OS to applications over to Linux and Open-Source. I have been a C# programmer and was an old VB programmer, so I have experience in those languages. However, most OO programming languages are easy enough to learn.

I will need client-server, database, security, and a good GUI for applications. We use Linux servers, MySQL, etc.

What is the best programming language that would allow for two licenses, one open-source and one closed-source, and would be easy to transition to from C#?

What GUI would best accompany that language?

Thanks for your input. Just thinking here...

Jacob

[xPlozion]

well, i don't program comp apps, but some popular gui's on linux are qt (used as kde's gui) and gtk (used as gnome's gui).

both are open source, but qt was frowned upon because of their qpl license not being as open as the gpl, but with QT 4.0, that's no longer an issue due to the fact that they switch to a gpl license.

i believe both are able to be used on many languages, such as C++, C, etc...

More Information:
GTK: http://www.gtk.org/
QT: http://trolltech.com/