I've Got a Project, You Tell Me The Language
csomar: if you happen to choose the Microsoft way, you'll have Visual Web Developer (and it's very Advanced) and ASP.net MVC (powerful for AJAX Application). Also you can integrate with it, Microsoft Expression to design your site when working with VWD!! You'll have also MS SQL Server which is very powerful and customizable. (and a big set of tools you can use).Drawbacks: The tools are very expensive (VWD pro to Expression to SQL will cost), the Windows hosting is also very expensive. If you have sufficient money then it's the best choice, look at the performance of stackoverflow.comanother drawback is there's a little "veryyy little" Open Source code (try codeplex.com) but still enough to make your own