Visual Studio is an incredible IDE. I hate working with any other editor simply because VS has turned me into a lazy developer. Still, for all its greatness VS has gaps in its functionality. Luckily, MSFT has exposed the VS API just like they have with Office.
Using this API you can add the killer feature you think VS needs to work the way you do. Even better, MSFT just released the VSIP Factory at http://www.codeplex.com/vsipfactory
This software factory creates the framework needed for a VS package. This allows you to worry less about how to connect your addin to VS and worry more about how to implement the required features.
I recommend taking a look. I also recommend visiting the Visual Studio Extensibility Portal hosted by Devx.com (http://www.devx.com/vstudioextensibility). This site highlights several products that integrate with VS and could provides good coverage as to the possibilities Visual Studio Extensibility offers.