In addition to the language itself, something to consider is the IDE used to program on each language. For example, although C# is more powerful that VB.NET, the editor in VB.NET is much developer friendly than the one in C# (VB.NET "guesses" more things for you.)

Keep also in mind that currently both languages a very similar BUT that might change in the future. For example, VB.NET will be geared towards "productivity" while C# will be geared towards "power" -- whatever those things would mean :)

One of the neat features coming for VB.NET is that edit-and-continue where you can modify the code as it executes and continue without restarting your app. I don't know if this will come for C# as well but somehow I doubt it (can someone confirm this?) This is something high on the priority list of VB.NET developers (they used to have it in VB6) but probably not for C# developers (they never had it.)