Visual Studio cannot be beaten, especially when free. C# is evolving towards better support for concurrency and functional style programming. F# is getting much acclaim even from die hard critics of .NET. You can use one framework for your entire application--be it frontend (ASP.NET MVC), backend, enterprise, even distributed computing on Amazon (MPI.NET). An added bonus is that the majority of professional programmers out there are familiar with .NET in case you ever need to hire (this is slightly more true outside the realm of web development and silicon valley).
Regarding support online, I've never had a problem self learning .NET, especially with MSDN, the ASP.NET community at large, and now stackoverflow.com.