I don't use an ad blocker
But I still don't see those nasty flashy-background ads on The Register (unless i'm on someone else's computer, in which case my first reaction is 'eww').
The only downside is that it breaks functionality on some websites (especially badly written ones) until I whitelist a whole domain. I often have to hunt a bit for the "functionality" scripts on a page, avoiding those which are "anti-functionality". But it's a small price to pay IMO for avoiding having my data slurped, and not seeing intrusive ads.