>What about if I don't want .NET enabled app but I want to use C# and VB then? Is it mandatory in VB/C#? I don't think so..

Jess,
that's why this CLR is such a radical shift. Not only will the CLR be the only runtime available for those tools, each tool included will have to make sacrifices in order to meet up with the limitations of one single COMMON runtime for all compiled apps. This will even break backwards compatibility but there has been mention about conversion routines to bring apps forward from version 6 to version 7.