These days I live in web browsers and all of my day to day work is browser based. Since I moved to Windows 7 I have had an issue where by Chrome and Firefox would take ages to connect to my local IIS instance. After suffering this for some time I decided to get to the bottom of it.
As it turns out (and there are a lot of false claim on Google!) it is as simple as ensuring you have 127.0.0.1 localhost uncommented in your hosts file. The hosts file can be found in \Windows\System32\drivers\etc. It would appear that if you use host headers for local development work then without this uncommented you are hitting the public DNS servers from what I can tell.
I should add that I am not running IPv6 and so did not enable ::1 localhost but you should if you are running on an IPv6 enabled network.