Marketplace has a couple bandwidth testing apps but nothing compares with BandWidth, which released v188.8.131.52 today. The app can now connect to 26 server locations around the World, or there is even an option to use your own server. You can use a Small or Large file for each location, and the app now tests both Download and Upload speeds in Mbps. Total time of test is also recorded. There is a nice graphical view while the test is running. BandWidth now has a History page, so when you are walking those street of NYC, behind Doug Simmons, you can log the bandwidth history and compare notes later. You can also select one server as a Favorite, Best of all the app is FREE. So what are you waiting for, download BandWidth today and have something complain about at the water cooler tomorrow.
You can find BandWidth here in Zune Marketplace. Note that you need Zune on your PC for the link to work.