I was working with CSS menus last week and once again learned lots about the scurge of cross platform cross browser support (MAC IE in particular). On my travels, I found http://flumpcakes.co.uk/css/optimiser/ which is truly excellent, every css I threw at it, it managed to optimise.
Another which i could not live without is the 'web developer' extension for Firefox. This too is truly excellent and has everything you will need for testing and debuging. I also use the User Agent switcher extension for testing too.
While looking at Extensions I cam across MozEdit…. Wwwwwooow, is the only owrd for it. Brilliant. The best part is the function view. I will definitely be keeping an eye on this extension in the future.
Another one worth mentioning is quicknote… excellent
RSS auto Discovery is something I have to get around to implementing.