swa66 - 8:07 pm on Jun 30, 2012 (gmt 0)
I'm using the for-pay maxmind database on an IP to country level: it rocks.
Their free ones: they had enough errors bad enough to not want me to continue to use them, but once I tried the for-pay one: I've immediately signed up for autorenewals. I've so far found one error and they corrected it in a matter of days.
Integration of it is simple enough, and it's fast.
Their apache module makes it really easy and gives it in the environment and makes it usable in e.g. rewrite rules.
They have a more detailed IP to city level in addition to the country level one (which I'm using).