firefox, the sneaky culprit
i started writing some code using C# and the ASP.NET framework a little while ago and noticed that running my scripts locally was painfully slow, so after Googling the problem for 5 minutes, i discovered that the issue was firefox-related and not .NET-related.
http://weblogs.asp.net/dwahlin/archive/2007/06/17/fixing-firefox-slowness-with-localhost-on-vista.aspx