Dreamweaver 4 is amazingly powerful. It is a WYSIWIG editor that will tie in with a HTML editor. The one they give you is Homesite, but I prefer to use LiquidFX with it.
Many people annoyingly think that having Dreamweaver will turn them into the best designers on Earth. This is not the case! It will assist you, but will not do your work for you.
With Dreamweaver, you can create a template page that you can use to make up your site, and, when you want to change something on the template, all other pages will be updated. This is VERY handy. As is the global search and replace, the link checker, and the browser compatability checker.
Dreamweaver as a WYSIWIG editor creates very clean HTML, and has a HTML editor built in for any minor changes. It supports Style Sheets, with a built in editor for them, and also supports layers, with an option to turn layers into tables and one to turn tables into layers. The transition isn`t always smooth, but if you want to have maximum control over the placement of things on your web page, making it with Layers and then moving over to tables is a good idea.
There are lots of `behaviours` available for download for free from various sites on the internet. These are special scripts that will enhance your web page.
Dreamweaver integrates well with Fireworks, and the two can be bought together at a discount, which is well worth doing.
If you want to edit ASP or PHP or anything like that then I`d recommend DW Ultradev, but for anything else Dreamweaver 4 standard is great.