You may want to just jump to Visual Studio 2008 once it comes out. It has a multi-targeting feature that allows you to target .NET 2.0, 3.0 and 3.5. I expect they will try to keep this going for future versions of the framework.
Also, if you like ASP.NET 1.1 projects you can use Web Application Projects which were included with the latest service pack for VS 2005.
You may want to give the Website Projects (not Web Application) a try. That was the model that was intended for ASP.NET 2.0 and it does have some features that you cannot get the other way. One is page-level compilation which is great during development. You
can work on a single page at a time and when you want to preview it you do not have to wait for the whole website to compile.