The Associated Press just served me an ad for fake anti-virus. The entire page was taken over, and forwarded to the malicious site, within seconds of opening the news article, every time.
An ad blocker isn't just something to hide some annoying eyesores, it's a vital layer of security.
If you have friends or family who might fall for fake AV or "windows technical the department" scams, they *need* an ad blocker. No site they visit can be considered "safe" unless it simply doesn't have ads.