I had a reader email me asking about SharpMap asking how “viable” it is? Well that is always a hard question to answer, but if you look over on CodePlex, SharpMap is the third most popular project. I know a few people who are developing with SharpMap and many more that are actively looking toward doing so. I’d say if you are looking for a lightweight library for mapping using .NET, SharpMap is probably one of the best choices out there.
**Update - **check out Bill Dollins’ post on SharpMap’s viability.