I\'ve some experiences on build application with Asp.Net, but now MVC frameworks become more popular. I would like to try building new multilingual web application using with As
MonoRail and ASP.NET MVC are fundamentally very similar, you should be well off using either one of them. MonoRail has existed much longer and has therefore more higher level features.
The main strength of ASP.NET MVC is it's routeing engine, to be fair MonoRail has pretty much an equivalent routing engine, and with some modification you can use the ASP.NET MVC routing engine with MonoRail as the routing engine is not really in ASP.NET MVC but in System.Web.Routing (Released in .NET 3.5 SP1). ASP.NET MVC and integration with Visual studio is also a plus, and will probably get better as we approach RTM of v1.
The MvcContrib project contains some great view engines, like Spark, NHaml and Brail. No one could be considered "Best", A personal favourite is Spark. For more on spark: http://dev.dejardin.org/documentation/syntax
The WebForms engine has intellisense which is a great advantage that to my knowledge all alternative view engines lack.