Optimum development framework for browser based deploy anywhere CRUD enterprise app?

What framework/language would you choose if you were starting a new development project with the following requirements? (I know that these are probabl开发者_高级运维y unrealistically ambitious, but I am hoping to understand the latest thinking and to at least get pointed in the right direction).

Must haves: Browser based client. Robust Server deployable on Windows or Linux. Depoyable as an SAAS service. Good protection of IP. Can create multilingual apps. Long term future stability of language/framework (>10 years). Needs to be able to upload and handle images, CAD files etc.

Nice to haves: Easy to find good, low cost developers. Easy/efficient to program. Low deployment cost. Server deployable on Windows or Linux for rare single-user standalone installations. Open source.

Many thanks, Michael

I'd sugest Ruby on Rails, Django or the Play framework.