Dreamweaver is your HTML/CSS/other coding tool. You use Dreamweaver to produce the text files that contain your markup and code.
Fireworks is the tool you use to graphically design your layout, then slice up the parts of that layout that should be images in your Web page, export those as images so that you can construct your page (/site) in Dreamweaver.
Fireworks is not a WYSIWYG coding tool. You can use FW to produce mockups of your layout for approvals, but the code is not robust and it is not intended for live sites.
Summary: design your layout and produce your graphics from Fireworks; build your pages in Dreamweaver.
I have a Web Premium CS4 suite myself, so here it is:
1. Fireworks is for producing graphics for Web, screen, UI (user interfaces), etc. Think of it as of a "Photoshop + Illustrator for Web/screen" -- sort of a lighter editor intended for screen graphics only. Fireworks is almost equally good with vectors and editing bitmaps, but the final results can be used only on screen, because Fireworks supports RGB/RGBa only (it doesn't support CMYK colors and you need CMYK if you must print your work later). Fireworks is also good with creating mockups/prototypes of designs, because it is fast and intuitive to use, but you can at any stage create a full-featured design out of a Fireworks mockup, because Fw has all the tools needed for this.
In one word -- Fw is the perfect screen graphics editor! Create your visuals in Fireworks and then later simply...
2. ...continue your work in Dreamweaver. Dw is the tool for creating/editing code -- CSS, HTML, XHTML, JS, PHP, etc. Some use Dw as a WYSIWYG editor, but I use it mostly as a coding tool -- it has code hints, integrated FTP/sFTP, code coloring, so I can use it for creating and editing the HTML/CSS for the designs I make. So you create the graphic design in Fireworks and then create the code in Dreamweaver (or at least, this is my workflow;-).
You can also use Dw as a WYSIWYG editor, of course (but code which we can create is always better than code automatically produced by any program, incl. Dw;-).
3. Illustrator. This is a vector editing program. You can use it for screen and print. It is more powerful than Fireworks, but more complicated to use. Anything vector and/or print, and I would go Illustrator way. In case I will create vectors for screen/Web, then I may use Fireworks equally well. But for extremely complex vector work, Ai might be better suited...
4. Photoshop. Well, you edit photos with that! Basically, a bitmap editing tool. You can also produce graphics for Web/screen in it, as well as work with some sort-of-vectors, but I would never do this. Fireworks is simply better. If you need print output and/or editing of bitmaps (digital photos, for example), I would recommend Ps for this.
5. Flash. This is for Flash editing. You can also use Flash with a tablet (it is very intuitive when drawing with a tablet and a pen).
6. Acrobat is for creating PDFs. It has some more advanced uses, of course, but I rarely use it for them...
7. Bridge. Not sure, never use it...
8. Soundbooth, Contribute -- someone else may help you better, I never even opened these...
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Hope this helps!