This is why I use Google's DNS servers (8.8.8.8, 8.8.4.4).

I was surprised by this rather recently, when my girlfriend and I moved in with her brother to conserve finances (both his and ours, since their other brother had just moved out leaving him with larger-than-payable bills). I mistyped a URL and it came back with an ISP-provided search page, which infuriated/surprised me. As it turns out, I only had the wireless connection set to use GDNS, but I was temporarily using a wired connection until I could buy a new wireless router (the previous one was a modem/router combo from the ISP, despite the fact that when I returned it the woman at the desk "corrected" me when I told her I was returning the router, saying that they don't deal with routers. I just smiled, did my business, and left.)