Developing a new application with .NET?

Question

I have to develop a basic "line of business" application with the usual functionality like orders, stock control, sales, reports, etc.

I will use WPF to develop this application to run on Windows but I want to develop it "open" so I can do a Windows Forms application using the same structure (maybe to run over Mono) or even a Silverlight module. Can someone that did something like that (and survived) give me a sugestion on a guideline or something like that where I can find good practices? I'm a Delphi developer with some intermediate knowledge on C# but there are so many "amazing" libraries, frameworks and patterns that I'm a little lost on what would be good for that project.

Something like: Use EF (maybe wait for ef4?) or nHibernate, or ADO.NET, and expose your data using WCF, or webservices, or forget Mono because of the flexibility loss, etc. Can someone give me a tip on how you would do it? If someone has a bad experience in this type of project, it would be nice to hear from you as well. There is a lot of learning in the wrong decisions too :)

Answer 1

Mono doesn't implement WPF, it's not even on the roadmap. I'm not sure about Entity Framework...

You could probably do it in Silverlight (which has an open source implementation), but it's not ideal for creating desktop (although it is possible since Silverlight 3)