www.opendns.com and Google DNS.
And should you have no DNS at all at a given moment (especially when setting a site up, or your neighbours router... YMMV), try to remember 8.8.8.8 and 4.4.4.4, which are Google's DNS, then you navigate to opendns.com to read their IP and put theirs as secondary. Google is 'not evil', but theirs is surely easier to remember than opendns... and you can sort things out once your side is up, and put any designated DNS, or your ISP DNS since it usually is lag-free, being very close to you.
Google DNS solves problems in a pinch, until you can retrieve more 'correct' settings. My ISP tends to have frequent DNS failures, for reasons unknown, so I memorized this little gem.
You're welcome.