There are some advantages to being able to develop in more than one language; but (in my opinion) the sophistication that comes from spending the same amount of learning effort on just one language far outweighs the advantages of knowing more than one .NET flavor.

Of course, the balance is intimately associated with one’s particular situation, and I am speaking in generalities.

Your latest post seems to imply that learning more than one .NET language would be necessary to develop components. If that is your meaning, you should know that the point is mistaken. As Peter & dparsons (is it Doug?) have said, “...I’ve yet to do anything in C# that I can’t also do in VB.NET.”