Sadly, you are already pigeon-holed because you are stuck with Windows and SQL. Stick with VS.NET for your platform. But also look into what JQuery can do for your front ends. There are many JavaScript frameworks that could also add a lot of value, but I recommend JQuery because Microsoft is using it in their new versions of SharePoint.

Bottom line: If you have to be stuck in Microsoft-land, work with them, not against them.