Bandwidth Monitor Pro is a utility that displays and logs your network adapters bandwidth usage. It supports logging of all your network adapters at once and has a detailed transfer history.
Included is an advanced alert system where you can set up rules to execute various actions like send e-mail, play sounds, execute files, shutdown, etc. when certain conditions are meet.
You can let Bandwidth Monitor Pro run in the background and it will log all your incoming and outgoing traffic for you to view later in the transfer log, or in real time if you wish.