BandWidth Monitor is a useful application that monitors the bandwidth you are actually using in your connection. BandWidth Monitor offers a very clear interface with actual information on the connection (upload and download speed, bits sent and received) and also real time graphs and long term logs, etc.
Also, you can review detailed statistics with all the TCP/IP information, change the icon in the system tray, and select the interface you want to use to monitor the connection. BandWidth Monitor works with modem, DSL, Cable, etc.