^ I disagree, Lion is not just window dressing it is upgraded functionality, starting with native 64 bit compatibility, but that is not my reason to reply to your post.
My reason to respond is to counter your statement about the latest CS version and LIon. I have not upgraded to CS 5.5 at all AND I also have some CS4 apps running (first of all Photoshop CS4 alongside PS CS5 so I didn't have to upgrade some third party plugins), in MY experience, CS4 will run under Lion, and you do need to upgrade some Java thingy for both Cs4 apps and CS5 apps. But once you do all is well.
As far as other third party apps, not having issues there either, many apps want an upgrade fee, and most will run under Lion, but just run better with an upgrade or have extra features, therefore I only upgrade if I need the new features, so far the only thing I have lost is the ability to use MS Word 2004, but didn't use that anyway, replaced Word with Pages and NeoOffice and the other app is QuickBooks, which I hated with the passion of a thousand suns, I use CG Invoicer for billing clients, so much better.
Loving Lion here, and just need to buy some more memory and I will also be upgrading my 2007 MacbookPro (my brother updated his which is the same model and hasn't had any issues with Lion)