I don’t think it will be a huge shock to the system to go from CS to CS4, unless you have a lot of dependence on ImageReady which left this world as of CS3. Generally, you won’t see massive differences to processes that you already use–you’ll just see nice improvements to those and a bunch of new features that may or may not be useful. For example, motion tweening is done differently in Flash CS4, but you can still use the old way which they now call “classic.”

To be honest, CS4 is kind of there in terms of diminished returns when upgrading. Most of the new features, unless you’re very involved in video (Premiere/After Effects), are cool but not the things you need on a daily basis. Some of the performance and integration improvements are nice, but any other software company would have called this a .5 update.

I think the way you’re going about updating–skipping a version or two–makes the most sense if you want to see some significant improvements when upgrading.

I am upgrading our department to CS4from CS(1). Will it be a big shock for us?

Also, at what point do you think Adobe users will reach a point of diminished returns when upgrading? What I mean is, how much better can these applications really get and when do all the new bells and whistles become just plain annoying and counter-productive?