The first thing that occurs to me is that if you did go this route, it's likely to use IE-specific stuff

Would this be avoidable with good coding, or is it pretty much determined that using .net restricts the user to IE?

As I think has already been said here, using .net doesn't mean you _have_ to restrict clients to IE at all. You can benefit from .net's features on the server and make your application faster (and easier) to develop while at the client end they still see the same html (or whatever).

Off the top of my head, I think answers to these questions will help make your options clearer:
- What type of data handling capabilities do you need at the client end?
- What is the nature of the data?
- Do you need to update the database with data sent back from the client?