Ah, yes I forgot to mention Firefox extensions! The two you listed are absolutely fantastic. There is also a similar extension ("add-on") for IE which is a must for testing, especially for FireFox Web Developer users!
To add to your list,
-Add N Edit Cookies
-CookieSwap (cookie profiles)
-DOM Inspector (default?)
-Tamper Data (highly recommended)
-View Source Chart
Another semi-related one (might be useful for you SEO folk) is SearchStatus, which shows your
PR and Alexa rank. It also has a context menu for quite a few more useful features.