ReSharper 4.0 has just hit beta! I have been using ReSharper for about a year now, and it is an awesome productivity boost. You can really concentrate on writing code, and let ReSharper take care of the little stuff, as well as some pretty major refactoring tools.

At the moment, I can get a special 60-day trial key for ReSharper if you email me and let me know you want it! I can't help but suggest you try and buy this software. If you can only have one addin for VS, then this is the one.