If you don't like your ISPs DNS you can always run your own... I think it is better than using those 3rd party DNS providers like OpenDNS and Google since I find their latency so poor.
Oh, one other thing that tends to effect speeds, especially with google. I tried using the DNS server setup on my new dedicated server (its in michigan), and it turns out I got google servers with much higher latencies than if I used shaw's or my own. Some how they are doing geo localization by DNS server, rather than your own. I thought they only picked the server based on your own ip, seems they don't.