I have always been annoyed when, as posts are rotated to the archives, the righthand sidebar content creeps across to the left. I’d rather have whitespace there.
After working through some of Eric Meyer on CSS today, I figured how to fix that. I just needed to add margin-left: 65%; to the side and sidetitle class definitions in the stylesheet and then tidy up some of the elements in the sidebar. There are a few serverside includes in there and I needed to remove any div tags from them to make everything work right.