Chris Holmes commented on my thinking for tools, but I think that he missed a crucial distinction that I made (but not clear enough).
If you require a tool in order to work effectively with something, this is an issue. By requiring a tool I mean something beyond VS + R#, which are the bare minimum stuff that you need to be effective in C# (it does says something on C#, doesn't it?). The Entity Framework Designer is a good example for something where I think that the dependence on the tools indicate a problem. I have been corrected about requiring the SCSF to work effectively with the CAB, which was good to hear.
Tools can make you more effective, but I think that you should always learn without them. Case in point, I am currently teaching people about .Net (I'll have a seperate post about it soon, I promise) and teaching them stuff like NHibernate or Active Record would be actively harmful for them at this stage, when they don't understand the basics of ADO.Net completely yet. In my opinion, it is always a good idea to know what the tool is doing, why, and where its shortcomings are.
Oh, and about the program in notepad thing, I don't program C# in notepad (usually), but I have written fully fledged applications in Boo from notepad and the command line. Boo makes it easy & painless to do so, and it is a pleasure (and painless) to work with it.