Tile is probably a better material than wood for using outside on top of cement. It's more durable and will be more practical in the long run.

I don't think wood will work, too much moisture and temperature changes.
How about a garage floor epoxy finish?

Thanks. We are ditching the wood idea for now. We just applied a concrete stain today so we'll see how that looks when it dries. If we don't like it, I guess we'll go with tile. But so far, it looks pretty good. I'll try to post a picture later.

Thanks for the suggestions!