.net's a great platform, but there's one BIG pitfall I'd worry about. The WS-* stuff that comes with C# should really be called MS-*. Despite claims to the contrary, the "Web Services" stack in .net has zero interoperability with PHP, Java and other languages.

At least one provided of "Web Services" went bankrupt because of their platform choice. I worked for a company that needed to connect to their system from PHP. Well, it took me two days just to figure out how to connect to the non-standard authentication "standard" implemented in Microsoft's MS-stack, and then there were more interoperability problems. We found another vendor that offered XML-RPC versions of their APIs AND sample code for ASP, JSP, PHP, Cold Fusion, you name it. We were up and running with their competitor in 15 minutes.

The server-side stack that supports ASP.NET AJAX, on the other hand, isn't so bad. I've been able to reverse-engineer ASP.NET AJAX calls and call them from PHP quite quickly, since they use industry-standard JSON.

I think that the overall mechanism where ASP.NET pages are written in XHTML and can be manipulated by the DOM is the best templating system in any mainstream platform. Beware the web controls, however -- they've got fundamental flaws that mean you'll never write a reliable and usable web application of any complexity with them, not to mind that they don't work with the modern MVC style. I think, however, you could build something that looks similar that has a sane mechanism for keeping track of state -- that would be a dream platform to work with.

@paul_houle,

Well to be clear I'm not suggesting ASP.NET WebForms, but rather .NET in general. This means you can follow MVC in .NET with ASP.NET MVC or MonoRail. As for as MS-*, you don't need to use them if you use WCF.