I use DNS level ad blocking. My DNS servers are set to 188.8.131.52
About 88% of the sites that I visits are free of ads. In fact these DNS servers even block the annoying ads on places like Hulu, Joost, fancast, and southpark.com.
I usually get surprised at the amount of advertising out their when I am on a public computer, I'm so used to browsing sites without ads.