Give me Packets!
I have been troubleshooting “network” problems for over two decades. From mom and pop small businesses to Fortune 10. Literally thousands of companies. As far as tools go, I’ve used just about all of them. From the Network General Sniffer, Novell LanAlyzer, Optimal’s Application Expert/Vantage, Compuware Ecoscope, Cinco NetXray to Wireshark and back.
You would be hard pressed to find something that is somewhat mainstream that analyzes packets that I haven't used to find and solve network and application issues. I’ve have also used the majority of the popular APM/NPM tools on the market for monitoring Network and Application Performance (I won’t list them). The one thing in common is that they’ve all been useful in their own right. Understanding at a high level of what traffic is on the network and an inclining of ‘potential’ application performance issues.