In Quicken 2008, they've replaced Classes with Tags. Personally, with only a very limited amount of time spent with the program, I don't see the point in the change: they seem to work about the same. One problem I have with Tags is that there's a Tag field in the Register instead of the Class just being appended to the Category (separated by a slash). That's no problem when you only have one Category. But, if you have splits (which almost all my transactions do), then along with the Category field saying "--Split--," you now also have a Tag field saying "--Split--" (and the Tag field's split isn't enterable or editable -- that's done from within the Category split). All it seems to do is clutter up the Register. It's possible to remove the Tag field from the Register entirely through the Options area, but then you can't see how you've Tagged (Classified) your transactions. I'd say that leaving the Tag field in split transactions entirely empty would have been a better solution for Intuit to use.
Dave