I would say go buy a nice quality (B+W/Schneider) multi coated UV filter....it's not that exciting, but I guarantee it will save your ass (and your lense) someday. If you've already got one, then invest in a B+W linear polarizer- indespensible for shooting outdoors. They can be had for just under 100 bucks. Again, not that flashy, but they will save your ass and improve your shot quality.
rogar-BigGrin(DBG) 