I've pondered this basic question as well.
Let me throw this "myth" at you: I've read that concrete floors (Like a basement) suck the "life" out of drums and HAVE to get off the floor and be put on a riser. Any truth to this?
I'm looking at converting a garage half to a project studio, and space is precious. I was considering putting down a wood floating floor (About 1" off the concrete, or whatever is the least amount and feasable) to help improve the sound. Now I'm hearing that concrete and wood will do similar things in this thread. It makes me wonder... is it worth it? Should one just leave it concrete and drums can go right on there and still sound good?
After treating the small room, I was considering a mix of wood paneling to liven it up.