One of my biggest pet peeves about Resharper was all the "Resharper" folders it puts in your solution.  In addition to making the project folder messy, it can mess up your repository bindings if you have multiple people working on the same project at the same time.  Then one day I discovered the setting for this.  The Resharper menu is really poorly designed, but the option is there!

Go to the Resharper menu in VS2008, and click Options.  Right there, at the very bottom of the first page, you will see the setting about caching.