Foam insulation is best for finishing a basement because it delivers excellent thermal performance and it’s not affected by moisture as much as other types of insulation. After all, basement rec rooms are holes in the ground, so liquid leaks and moisture infiltration is always a possibility. In my experience, a three-prong approach works best when insulating a basement. Rigid sheets of foam insulation work very well on walls, and spray foam is the best way to insulate the place where floor joists meet outside walls up at the ceiling. Nothing even comes close to the effectiveness of spray foam in this location. The warmest and lightest weight rec room floor system currently on the market is called Barricade Plus. They’re a high-load 2’ x 2’ subfloor tile made of high density foam. The foam is firm enough to support most kinds of finished floors, and the 1” thickness delivers R5 of insulation.