I would vote for ASP.NET: is easier and faster for developing than other languages, it can be precompiled, object oriented, has a self and easy AJAX implementation (without user javascript code).
I don't like script languages, like ASP and PHP, because the code is "dirty" between HTML and script...with ASP.NET 1 file is for HTML (presentation) and the another for code (LOGIC)...easy to read and modify (but is possible to do "dirty" pages like PHP or ASP).
I don't know python and ruby for now, so this languages are out of my post