After searching high and low for what might be causing a delay with typing with VS2005 and R# I have stumbled upon a solution that seems to work pretty good for me and thought I would share.
1). Turn off the navigation bar. Tools > Options > Text Editor > C# > Uncheck the Navigation Bar. You lose the top two drop downs but Ctrl+F12 in R# is more useful for me.
2). Turn off track changes. Tools > Options > Text Editor > Uncheck Track Changes in the Settings group panel.
Doing these two things has for the first time made R# 2.0 intellisense useful for me and has pretty much gotten rid of all delays in typing and backspacing. Your "mileage may vary" but I hope this at least helps a few people.