Having a quick Domain Name Server is very important for that lightning quick internet experience. Fortunately there are ways for you to easily figure out which DNS works best for you.
Namebench as described at its website:
It hunts down the fastest DNS servers available for your computer to use. namebench runs a fair and thorough benchmark using your web browser history, tcpdump output, or standardized datasets in order to provide an individualized recommendation. namebench is completely free and does not modify your system in any way.
All you need to do is download the program and run it. After a few minutes of churning out calculations the program will tell you the best DNS settings for your system.