GhostDoc
Besides ReSharper, there is only one other Visual Studio plugin that I cannot live without — GhostDoc. If you have not used it before, it basically generates XML comments on your code and makes a best guess on what the comment summary should be. This feature is pretty standard for Java IDEs (except for the actually generation of the summary for you), but it is yet another thing that is missing in Visual Studio.
If you follow good naming conventions in your code, then you should get pretty decent results on the summary it generates. It is definately a keystroke saver and makes documenting your code somewhat infectious. When I see code that is undocumented, it is really hard for me not to hit Ctrl-Shift-D and have GhostDoc document it.
There are a number of different features/options and I am definitely not doing it justice in this short post. The best way to find out if you like it is to try it out. Small download and quick installation.