Traffic Info is a nice and free gadget that will let you enjoy on your Desktop road traffic flows, real-time traffic conditions in your area, in order for you to avoid congested road sections.
Traffic Info gets data and maps from Google and supports major cities from all over the world.
Even if traffic data are not available for a city, you can still use this gadget to use the Google map service on your desktop. Althought the gadget offers also a larger size, you can even open (with just a mouse click) the current map and/or traffic info to your browser for a really large view.
Check this post for a Network (upload/download) traffic gadget