Inherisense
When Sam Gentile spoke at last month's VTDotNet Users Group meeting he used TextPad as his editor and made a great joke about people in the room suffering from “intellisense withdrawal.” I have to admit that I am an Intellisense JUNKIE and can't get enough of it. It is part of my thinking process when naming variables, trying to avoid duplication to avoid less typing before my selection appears in the intellisense popup.
I was so impressed to see intellisense spring into action even when I was declaring a base class as shown in the pic below. Intellisense everywhere! (including .ascx and .aspx files please....)