[Microxot]

I think you first need to decide what you are going to be using your truck for. If your a city boy and the truck is just transportation (i.e. not going to use the bed) then leave it open. Why spend money on something your not using.

If your going to be using the bed to minor hauls from time to time but not worried about people taking things, then buy a bed mat. If security is a concern, then get a hard cover or a retractable. Be sure they are lockable.

Now if you know you'll be hauling stuff from time to time, that you don't want to scratch or scratch the bed of the truck, look into Rhino Lining. It grips better than Line-X.

If you are serious about hauling really heavy stuff all the time, then look into Line-X.