I use NPE a lot for testing feeds and feed behavior and it would nice to have a few features for working with the NuGet Local Cache:

1. Some indication of whether a package was loaded from the Cache or the web - Perhaps in the title bar? "Foo.1.0 (from Cache)"
2. A command to clear the Local and Memory (if any) package caches, perhaps in the Tools menu
3. A checkbox on the Open from Feed dialog to skip the cache and force re-download of the package.
   

These are in priority order, i.e. #1 would be VERY useful, #3 is a nice-to-have but not essential, etc.