that's a local speed test. Blizzard is hosted on AT&T networks. The real question is, what kind of connection does your ISP have to AT&T.
edit: With TF2, you can see the server's IP address. Try to do ping <ip> and see what. If you see a low ping there, but you get a high ping in game, something more sinister is at work. Either something on your network is slowing down TF2 or your ISP is doing that.
tracert <ip> could also give you valuable data as it shows what your ping is to every hop between you and the server.
The route taken is very important
You'll notice that German Town is 1/2 the distance that Chicago is, yet it gets a worse ping.