It's fairly simple to set up a local DNS caching server. This does tend to reduce the latency when browsing the web a little. You don't even need to fiddle with IP validity durations (time-to-live): merely refreshing every few hours instead of several times per page visit is an improvement.
Under Debian, Ubuntu and derivatives, first install the
resolvconf package. Resolvconf automatically handles all DNS source maintenance, so that whenever you connect to a network, the associated server is registered in
/etc/resolv.conf (if you don't have a DNS caching server) or with your DNS caching server (if you have one).
Then, install a DNS caching server such as dnsmasq or pdnsd. Pdnsd is more advanced on the DNS caching front, as it can save its cache to disk whereas dnsmasq's cache doesn't survive across reboots. Pdnsd can also be configured to keep entries longer than they should be (which you do at your own risk).