The problem with sites that block users using adblockers is that those sites are terrible anyway. It means they are too bloated and/or entrenched in old ways to change their revenue model. Users that enjoy your site because you provide content will gladly support it if you give them a reasonable way to do so. Putting up a bunch of crappy ads isn't the best option. That's just a good way to eventually alienate your readers/users, especially if you essentially escalate it to an arms race where you block the blockers and force them to either go elsewhere or figure out how to circumvent your blocking of their blocking.
At the very least be selective with ads, and only directly partner with businesses you know sell products and services your readers might be interested in instead of being promiscuous with your acceptance of ad partners and networks. *elbows Purch/Anandtech*