I just found this site today called Speedtest.net.  This site will test your bandwidth speed, including your download speed, upload speed, and latency.  There are a lot of web sites out there that already do this for you, but this is the coolest site I've seen yet.  So check it out if you're curious about your bandwidth.  When you're done you can even post your results for other people to see.  Here are my results from work: