There are 4 linode nameservers. I need two (to configure as my domain hosts). Which two of those four should I pick?

(so far I semi-randomly picked ns1 and ns4)

It really shouldn't matter much, although you may have a preference on geographic location.

ns1 = Dallas, TX
ns2 = Fremont, CA
ns3 = Atlanta, GA
ns4 = Newark, NJ

If that doesn't matter to you, ns1 and ns2 get hit much harder than the others, so I'd suggest ns3/ns4.

-Chris

Your registrar should let you add as many as you like - look for an 'add more' button somewhere.

Note that "domain host" is different from "dns server for your domain".

My registrar let's me add as many host as I like, but only 3 delegations (picked from them). Whatever - this is more than enough, I am just curious whether there is any reason to pick ns1 over ns2 or ns4 over ns3...

Edit: just spotted reply in earlier post. Thanks.

PS DNS terminology rocks, only SSL is more confusing

I've noticed it takes 3 and 4 a few minutes to pick up changes after they're notified, I figured they might be REALLY busy with something.

I've never regretted having lots of name servers in geographically diverse locations, I use all 4.