The last few days since I installed openSUSE 11.4, I've had really frustrating delays with certain DNS lookups. zypper, for example, was taking 4-5 seconds to resolve each host when refreshed, particularly annoying if one just wants to search for a package and is forced to sit through a 2 minute delay. Happily, it is now resolved. Thanks to the discussion under this bug, I learned that placing the line "options single-request" (without quotes) in /etc/resolv.conf solved the issue. According to man 5 resolv.conf, this forces glibc to perform the IPv6 and IPv4 requests sequentially, and not not in parallel which can cause timouts with certain DNS servers and then the delays I was seeing.
Of course, you could also run nscd, which I don't for certain reasons, but still, all DNS lookups ought to be fairly instantaneous. Hope this helps someone. :)