My wife's Grandfather, senile in his later years would not throw out his old pants no matter how soiled or ruined they would get. "They don't make pants like they used to!" he would say at any suggestion of replacing them.
I have been evaluating the IE9 beta since it came out in September, and to my surprise it is actually pretty good. Microsoft has had its hands full with IE for so many years fixing bugs and supporting older standards that it is actually pretty amazing to see a product release from them that pushes forward.
This is a brief list of my Firefox Add-on recommendations. I use these to assist with site development, diagnostics, and so on. These add-ons increase my productivity.