What's the easiest way to monitor the amount of data moving between a single workstation on one interface and a single server on a different one?

What do you mean by "monitor," Steve?  What question do you want to answer by doing that?

Cheers - Bob

Just quantity of data. We have a piece of software that we suspect is a bandwidth hog. We want to run a transaction and see how many MB of data went back and forth between the workstation and the SQL server.

Web Protection -> Application Control -> Network Visibility -> Flow Monitor.

Web Protection -> Application Control -> Network Visibility -> Flow Monitor.