I've just been browsing through PCMag's Top 100 sites for 2009. They have divided the list up into two sections Classic and Undiscovered, and then divided the Classic into Apps, Fun, Info, News, Shopping and Tech and the Undiscovered into the same categories excluding News. I'm not sure why there's no News category in the Undiscovered as I would certainly be adding a few news sites to their Classic ones.
I was interested to browse them and discover that I regularly use 20+ of them (mostly the Classics like Facebook, Twitter, Picnik, Google apps, Youtube etc but some so-called Undiscovered like the World Digital Library) and I have played with others. There were half a dozen that I will explore personally and also some that I thought might be worth exploring for Web 2.0 classes either for the staff or the public, eg for travel.
However, I must say there were quite a few that I know I will never look at because I don't live in the US. I might be interested in restaurants in NYC if I were travelling there, but I really am not interested in US real estate or where to get a pet from a shelter in US. It would be interesting to see what an Australian list of 100 best websites for 2009 looked like, but maybe it's just too many to be focusing on for anywhere.