When we finished our basement in the last place, we used Dri-core. It has a dimpled plastic base with particle board on top. It was easy for DH and me to install because the 2 x2 foot pieces are tongue and groove. We laid tile overtop but you could install carpet or carpet squares. The dimpled plastic base forms a moisture and vapour barrier and if you get water in the basement, mold will not grow on the plastic.