Web browser tools for power users?

I've been around the web for quite a while and finding interesting sites is one of my hobbies. What do you guys use to organize your web browsing? What do you use to perfect your browsing experience? Any tips?

I use a plugin called 'morning coffee' to bust open all my regularly visited sites every day, quite a few times a day. It's pretty helpful.

I also use a social bookmarking & networking plugin called Stumbleupon. Here's the page I made with SU: http://projectdp.stumbleupon.com/ Basically it's a toolbar that lets you make comments on websites. For example a few months ago I reviewed techwarelabs: http://www.stumbleupon.com/url/www.t...com/community/ that you can read about. Um. Oh the best part is that you can "stumble" there's a button that loads a random page within the limits of the interests you have.. for example if you like religion you can select that, hit stumble and it will find a random sites tagged with religion. Pretty spiffy.

I have firefox by the way. I don't really use any other plugins right now. I also have spurl that I mostly ignore. I have a del.icio.us page that never gets updated as well: http://del.icio.us/projectdp