[ale] Recommended public DNS server

[aaron]

My Comcast service went out briefly Friday night.  Upon investigating, I was 
able to confirm that I still had connectivity with ping to a known IP number, 
but the problem was that my assigned DNS servers were down.

The incident made me realized that it would be handy to have some fallback IP 
numbers to plug in, so I'm looking for recommendations on public DNS service 
(or commercial DNS servers who don't mind occasional guests).

Thanks in advance!

peace
aaron