Social websurfing: stumble upon a ton of cool sites

One of my new favorite ways to surf the web is through stumbleupon.  I signed up for an account, added a toolbar on my browser, and selected areas of interest, and voila!  I just click the "stumble" upon and it brings me to websites that others have "stumbled upon" in my interest areas.  More and more, surfing the web will become more social/communal.  If you like this concept of having the power of crowds lead you to cool websites, you may also like newsvine (which seems more political) and digg (which seems more for techies & guy stuff).