What is the best way to develop apps for Ubuntu?
I want to develop software for Linux or cross-platform. I want to work with other open-source and non-profit developers. I want a place where Ubuntu or other developers come to start open-source or commercial projects, and we can join the projects or start our own projects.
I know there are social coding sites, but where can I start the project, and invite people or let people join? Then we can submit software to sourceforge.net. I know we can start projects at sourceforge.net, but is there anything more dedicated for Ubuntu developers, especially for Ubuntu and for the Ubuntu Software Center?
Would you recommend Launchpad, sourceforge.net, github, gitorous or others?