I use netpersec. A little app that sits on the toolbar and monitors download and upload. A small square split into red for down blue for up.
Gives me all the information I need to recognize any unusual activity. Currently the top half is blood red because I am downloading a movie. There is also some activity on the blue because I am uploading. If the bottom half is all blue I normally get very suspicious.
netpersec is a very small app. Had if for years. Was free and you should still be able to find it for free.
