JAMESP Path Analyzer Pro is awesome. Besides being just a cool program to use, it actually helps solves problems. When we experienced a network issue and were arguing with our ISP / network provider about where the problem was, Path Analyzer Pro helped us determine where in the line things were messing up. Then, by exporting the report and charts as images and droppping them into an e-mail to our providers (all it takes is one click in the app), it made it easy for even a non-network-person to see where the problems were and how bad they were. This program has my vote for a must-have network utility.
(Version 2.1)