I have not tried Expression but Dreamweaver is amazing. It has great interchangeable layouts and many shortcuts. You could probably learn web design just from using the program.
If you dig deeper, there are many advanced site management features where Dreamweaver allows you to make changes to every page on your site. It has a preview pane which shows you what you are doing as you code it.
I have been using Dreamweaver since I started designing and I am still discovering its features. It will change your career for the better.