Using illustrator 5.1 with the 5.5 upgrade on a new MacBook Pro 10.8.2. This is a new MacBook and I just migrated data to it. The original source desktop iMac 10.6.2 is working just fine with no issues.
I am only able to use the font menu in the strip bar (sorry, don't know the formal name - it's the optional shortcut menu just below the File menu bar). Both the pull down font menu on the tool bar and the type character pane crash Illustrator the moment they are touched.
update: Illustrator finally seems to have stabilized after several rounds with preferences/permissions.