Currently I have ReSharper installed to help me develop and edit code, and made a good layout for my Visual Studio (2008) over two screens. I have changed the settings of the text windows (mainly the output Window on the right) to have a black background and smaller text.
I tried SlickEdit gadgets yesterday, but it doesn't perform very well in my opinion.
What other addins or trick do you use to further customize or enhance your Visual Studio experience?