It gets more and more interesting for us to determine, where our users pull their traffic from etc., also to determine what Internet Exchanges we should connect to next, like LINX, AMS-IX or DE-CIX ?
For that purpose, we've got a trial for IBM Aurora, the Quagga BGP gateways have been installed with pmacct netflow probes a while ago. I had tested various open source solution for analysis, but wasn't quite happy with the result. ntop was working quite ok, but Aurora beats all of them. Obviously it's a commercial solution.