I used to, but got tired of it. ABP just seems to make everything slower. Back in the day, an ad blocking hosts file worked like magic. No memory leaks from the browser or other problems. Ad loads failed at name resolution time and failed very quickly.
Also, to be fair to internet marketers, ads are much better than they used to be. The old 'punch the monkey style' ads are long gone outside of.. how do you say, questionable sites. Auto-playing videos are rare. Once in a blue moon I actually click on ads that are targeted to me. The system sometimes works.
Railing against ads just seems like a poseur-ish thing nowadays. I also feel especially bad blocking ads from sites I visit regularly. Its a dick-ish thing to do. It just seems better to keep open a dialogue on what we consider acceptable ads and what we consider unacceptable ads. Or help the site owner understand that they're better off with targeted ads or selling their ad space themselves, than joining some shady affiliate group with generic "This school teacher is making $900 a day" crap or, heaven forbid, video auto-play ads (which are pretty rare nowadays outside of news sites/youtube where the content is video but you're forced to sit through 35 seconds of ad before you can see it.)
A lot of annoying content isn't ads at all, its dhtml/css 'pop ups' asking you for your email address or facebook login or survey or whatever. ABP doesn't usually stop those either.
Loudly proclaiming you must use ABP is almost like saying, "Well, I visit tons of shady porn and torrent sites, where its more or less required." The non-shady web just seems like a better place than during the early 2000s when Flash ads ruled. YMMV of course.