Several people will respond with different (and very valid) viewpoints. Here are mine:

1) The framework classes are much more important than the language

2) I've been talking to people who use VB.NET for the UI piece and C# for the application tier

3) If you've previously programmed in C or C++ or Java, you might feel a tad more comfortable in C#. If you worked heavily before in VB, then VB.NET might make more sense to you.

4) I personally use C#.

Some time ago, Cathi Gero posted a URL with that had some discussion items on the differences between the languages. I'll see if I can find it.

But above all...learn the framework.

Kevin