Don’t bother and don’t say you weren’t warned. There is nothing in Lion that is compelling enough to risk a production machine for.
If you're determined to keep CS4, Bob is right. Lion is a much better fit for CS5.5 or the upcoming CS6. Software updates and OS updates should move forward together.
I'm not determined to keep CS4 ... right now my pocketbook is determined! I've constantly wondered about this ... and finally decided to come to a forum to ask. I definitely respect both of your answers --- and thank you. I will be keeping CS4 and Snow Leopard and know that my world is going to be just fine until my pocketbook is overflowing with extra cash!!!
I had only purchased the Lion upgrade because it was very cheap. It sits here on the desk and I keep thinking it is silly to not use it. Now I will no longer wonder .... and the upgrade is being put away!