Fork Boots. I changed the fork oil at the same time and cleaned out the fork seals using the cut up milk carton trick. Seems to work well, and from the dust, mud and dead bugs that the boots have recollected it seems as if they will keep the forks and fork oil clean a little longer.
Bar raisers. I made these myself out of a couple of sockets (3/4" I believe). Simplest and most original looking mod ever. Some improvements to riding ergonomics.
Sheepskin. Radically improves comfort on longer travels, almost eliminates discomfort from road bumps and looks bad ass as hell.