I was looking at the new feature of VB10 and C#4.0 in the VS2010 CTP and it appears that they are becoming more alike than they are diverging. VB10 gets the explicit line continuation, no more "_", not universally , but in a fair number of places. I also gets auto implemented properties (C# 3.0 already has this) and collection initializers among other features. C# on the other hand is getting optional parameters, which have existed in VB for quite some time.
So it seems as time goes by there is really less of a difference between the two languages that in Version 1 of the .Net framework and VS7. So at what point will they become so similar that it will not be cost effective or desirable to maintain to distinct languages with exactly the same feature set? Granted there are still some differences between the two languages, but as time goes on, there is less and less that separate them other than pure developer preference.
I suppose that there will always be the "My language is better" kinds of religious arguments but it is becoming harder for each camp to point out the differences.
The VB10 futures doc can be found here.
The C#4.0 futures doc can be found here