i think you will get the most use out of a the HU and speakers. you can get a gallon of herculiner roll on bed liner for about $60. not a hunter so i guess i dont appriciate the gun option. it is fun to go target shooting oncec and a while but doesnt compare to not having to listen to tapes and radio and clean sound reprouction.
Im from a small farm community i would go with the gun if u hunt ALOT. but if not then u have to consider do u haul a-lot of things in your truck? If not i Would go personally with the speakers and stereo, Gun, Bedliner