I just have to weigh in on this.
I've been trying to adjust to CS5, from CS3, since November. It's now March.
My job involves taking apart and editing complex art created by other people... who have all different ways of working. The inability to see what a clipping mask contains when I click on it, AND the inability to edit the contents unless I first locate the perimeter of the mask and/or switch tools, has me working "blind". It's become a real battle to figure out how the previous artist set things up.
I've found workaround methods, but they're just that. I seem to be doing a lot more clicking, double clicking and tool switching, all of which are that much harder on hands that do this for 10 hours a day.
I need to be able to click on an element and know if it is part of a mask, what other additional elements that mask contains, whether the perimeter of the mask is aligned correctly, etc.
PLEASE make it a preference setting to handle masks and mask content selection the old way. When I'm building new art, I'll be happy to work the CS5 way. When I'm trying to figure out what someone else has done... please don't make me work harder than I already do...