Depends on how much you want to spend. On a brand new truck, I would opt for a spray-on bedliner. However, I always have a second hand truck used primarily for Home Depot/dump/suburban duties and have used roll-on kits with very good success.
@Vdubby18: I had a coworker do something similar to an old Jeep Comanche and loved the results. I have to admit, I would never think that this would look good on an Audi, but that is pretty cool.(No worries about waxing or durability now)
I have a spray in bed liner (Qwikliner), and have been very happy with it,Spray in.......... very nice, durable, doesn't fade, good looks, you can actually dump a load of rip-raff on it.
Roll in.......... looks ok, fades yearly, is a PITA when half of it peals and flakes and you have to remove it to get a spray in.