If Visual Studio 2005 seems sluggish or slow while editing C# source code, try turning off the Navigation bar (Tools / Options / Text Editor / C#). In a reasonably sized project, I went from being able to type 1 or 2 characters a second to full speed. Intellisense was just as sluggish. You might miss the Navigation bar though. I certainly hope Microsoft will vastly improve the speed and performance of VS 2005 in SP1. The quality of VS 2005 just isn't where it needs to be.