Why should I both Unit test AND Web test (instead of just web test)?
My current position is this: if I thoroughly test my ASP.NET applications using web tests (in my case via the VS.NET’08 test tools and WatiN, maybe) with code coverage and a broad spectrum of data, I should have no need to write individual unit tests, because my code will be tested in conjunction with the UI through all layers. Code coverage will ensure I’m hitting every functional piece of code (or reveal unused code) and I can provide data that will cover all reasonably expected conditions.