If you get a pair of shoes that are "touring" shoes or even some styles of mt bike shoe they come with a cover over the cleat hole area. You often have to actually cut the rubber out of the sole to even install a cleat. They otherwise look very much like normal tennis shoes/hiking shoes, with the biggest difference being that the soles are extra stiff. They will work fine without cleats and then when you are ready you can install them.
With this type of shoe you would only be able to use a cleat/pedal system made for recessed cleats - like spd's, crank brothers candies or speedplay frogs.
Road shoes on the other hand aren't really suitable for use without cleats and definitely aren't suitable for walking around on without cleats installed (of course they aren't real suitable for walking around period..... even with the cleats installed, but without them you run the risk of damaging the sole of the shoe). With road shoes your choices of cleat/pedal systems would be different.