I installed column-marker.el. I like the highlighting style better than fci-mode. Unfortunately, column-marker does not highlight bits of the window where the actual line is not 80 chars or more (or whatever its set to). Can this be fixed, so that there's a continuous highlighted strip at column 80? I saw that this issue used to exist in fci-mode, but was fixed. I didn't investigate carefully.
I suppose it's possible to configure fci-mode to display like column-marker, but I haven't investigated this carefully either.