What's wrong with C#? It seems like you like the language and are only concerned about the software costs, so Mono would be an obvious option to look into. And

What's wrong with C#? It seems like you like the language and are only concerned about the software costs, so Mono would be an obvious option to look into. And the compatibility has improved quite a bit, to the point that there are quite a few projects that support multiple platforms: http://www.servicestack.net/ http://www.servicestack.net/ http://nancyfx.org/ http://nancyfx.org/ http://monogame.codeplex.com/ http://monogame.codeplex.com/ http://monocross.net/ http://monocross.net/ https://github.com/markrendle/Simple.Web https://github.com/markrendle/Simple.Web