I'm having problems viewing CR 2008 reports with the current CR Viewer and the CR Basic Visual Studio 2008.
An update and partial resolution...
VS 2008 comes with CR 10.5. If you install a newer version of CR onto the machine, Visual Studio will use that version of CR. And...
There is a service pack for CR 2008 (http://downloads.businessobjects.com/akdlm/crystalreportsupdate/CrystalReports2008.zip) that is needed if you want to read reports created with CR 2008 in VS 2008. The current download of CR 2008 includes the service pack; you only need the service pack if you installed prior to March.
Still unresolved: The current Viewer does not work with all CR 2008 reports.