Sk-etchbook

I recently decided to place my grubby little mitts on a CS4 trial to be up to date when I finish the DDM course. I must say I'm impressed with Dreamweaver, they have really streamlined the work flow and embraced the growing technological trends. You can tell they have put a great deal of user feedback into this release too as the UI has been totally overhauled giving greater control and trashing some of the outdated and improper elements. The are a load of new features including:

Smart Objects
Place .psd files directly into the document (prompted initially for all the settings previously specified in "Save for Web") and they are updated like regular smart objects. You can also cut & paste directly from Photoshop, Dreamweaver will then remember the compression settings if you replace the cut image segment.

Live View
See your page design in real time as it would show in Safari

InContext Editing
Very clever new feature. You can now add editable regions to your pages which can be edited via a browser. Allows for updateable or duplicatable areas for simple CMS or news/blog functionality.

Related Files
Displays a tab for each file associated to the current document in view .ie .css or .js files.

Create AIR applications
This is fantastic. Web design functionality for the desktop it is so simple!

There are many more new features both in terms of functionality and UI but these are the ones I have played with so far. There is a great deal more support for JavaScript and Ajax now incorporated along with a barrel load of widgets and goodies which can be added from the exchange.