We should probably put on our Reality Glasses for this discussion. It's not just Syntactic Sugar going on here.
You will find that you can write code very quickly in Visual Basic.NET. That is largely due to some features that it has that C# does not yet provide: namely, the My namespace, which provides a plethora of functionality that C# developers have to frequently code by hand. (And that's a damned shame, if you ask me.)
I code in both languages every day. Coding event handlers for forms in Visual Basic is a snap, and it's VERY obvious what methods handle which events. It's not always as clear in C#. On the other hand, you can't always be as explicit in Visual Basic as you want to be, because Visual Basic does so much of the work for you. C# has the advantage of just getting the heck out of your way, and letting you get down to the nuts and bolts. Quite often, that's extremely liberating.
VB will let you invoke static/shared methods on an object instance. C# won't. You'll learn that the hard way when you try to port your code. C# will complain about unreachable code; VB doesn't care one way or the other.
But under the hood, when you get right down to it, it's all .NET. It all compiles down to MSIL. There will be minor differences. Visual Basic, for example, doesn't care about the case-sensitivity of names, where C# does. And the big gotcha there is that the CLR does as well. You'll realize that when you try to use reflection. Does that mean you shouldn't use VB? Nope. Just make sure you case things consistently -- especially your namespaces. (Namespace "My" and namespace "my" are two completely different namespaces to C# and the CLR, but they're the same to VB.)
Choose the language that makes you most productive, that reduces ramp-up time and maintenance costs. You may find that that means working with both languages. (We do!)
EDIT TO ADDRESS OP'S EDIT:
Refactoring tools are available for both languages.
Automated unit testing tools are equally applicable.
3rd party controls are going to be available for both languages because they're compiled down to MSIL.
Now, for IDE productivity tools, the one thing that C# has at this time that VB doesn't is StyleCop. That may change soon (and I hope it does), but I don't view it as a roadblock by any stretch of the imagination.