One of the GPanswers.com Team members like you, Rainer Pollmann, had a LOT to add after last week's discussion on IE8 settings using GP!
He made me aware of three resources you shouldn't pass up.. (thanks Rainer!).
Here they are:
Item #1: IE8 Settings Spreadsheet Why you care: Because you cannot use filtering in the GPMC with these new settings (Grrr..) so, using this spreadsheet is better than nothing.