I have carpet floormats in my rubber floored GMC... Works pretty well.
My Jeep has carpet in the front seats only, but it is destroyed,and really I just leave it there for heat and sound insulation. For a strictly wheeling rig, bedlinering the floor is not a bad plan, but as pointed out above, don't use liners with the "grippy" stuff if you want to clean up and look nice. (Rustoleum, Herculiner, etc) (And DO NOT use anything called "undercoating", because most of those products never really dry completely!!)
Both Raptor Liner and Monsta Liner have a somewhat textured finish, but both are pretty glossy and clean up very easily. They are not really "grippy" in my opinion. I'm using Monsta to do the bed of the Comanche, just to hide all the dents and scratches and make it look decent. They have a color that's pretty close to Rustoleum Desert Sand, so that'll be what I lay down.
If you really want to put something down that will last, take it somewhere and have it sprayed. There are many companies spraying really nice products these days. NONE of the DIY liner kits are worth a poo comparatively.