Oak if your buying a kit. Pine will dent/scratch just looking at it.
Teak or any hardwood for that matter if your doing it yourself.
Not much is going to hold up here long term but I'd probably start with some sort of marine product.
Speski OffRoad LTD, Cargo Solutions for Toyota 4x4's http://www.SpeskiOffRoad.com
"80 series, with a fridge"
1976 FJ40, Project with little progress.
2004 Starcraft 10RT