Google announces their own public DNS now. Some seem to think it's a good move and a fundamental threat to ISPs who are diluting the neutrality of the net. However, I tend to side with the conspirationalists who see it as an attempt of Google to gather even more information about what people do online.
Using the Google DNS you basically allow them insight into any connection your PC performs while it is online. Not about the data exchanged, but at least about what other computers you are connecting to, and not just during web browsing, but also email, instant messaging, chatting, peer-to-peer networking and so forth.
Of course my ISP provides their own DNS and uplink routers are normally configured to use the ISP DNS servers, but I bet Google's Chrome OS will by default use Googles DNS. Guess what I'm not going to use on my private machines.
Now, unfortunately ISPs are known to tamper with DNS queries of their users. If you ever tried to surf a non-existing site you probably found your browser displaying some "navigation aiding" by courtesy of your friendly Internet provider. While meant to be helpful towards their users it bears a threat as well. There you have an infrastructure which is specifically built to intercept connection attempts. While I can't say I actually appreciate this, the way Google harvests data is seriously creeping me out just as much.