I don't know if anyone else working with Photoshop CS on a Mac with OSX has run into this issue where your keyboard shortcuts using the Option key, Shift key, or spacebar no longer work...
But in case you have, I finally found the fix this morning while I was at work after another artist suddenly had the same issue and was freaking out (this after beating my head against my monitor for the past 2 weeks and no help from our IT department who are Mac agnostics - why then is the art department stuck with using Macs...OK, OK, that is separate issue....<sigh>).
Anyways, here's a link to the Adobe document that has the info: a quick fix as well as a long-term solution:
I post this info here in the hope that another Photoshop user doesn't have to put up with such a silly problem (Microsoft's Entourage conflicting with Adobe software), and because I was so happy to find a fix that actually worked. :bounce: