90% of the time, when I unplg my 17 MBP from my 30" external cinema display, later on at home, I open the lid and I get this screen which I can't rectify so I have to force quit! any ideas?
For starters, I'd run an Apple Hardware Test and see if the wares are still good.... http://support.apple.com/kb/HT1509
And much as I hate recommending it, maybe you'll need to turn it on and off instead of sleeping to prevent this until you get it sorted out, lest it eventually lead to a corrupted drive and data loss.
Retrieving data ...