It depends on what you're doing. I think there's no real difference between VB and C#. The both of them are .Net languages and they're compiled in IL.
More info? Read this:
http://devlicio.us/blogs/robert_dunaway/archive/2006/10/19/To-use-or-not-use-Microsoft.VisualBasic.dll-_2800_all-.NET-Languages-could-benefit_3F002900_.aspx
