Speaking of floors, Sandor mentions the benefits of having a wood floor but only in the context of putting one over a concrete slab. My last two shops were built on piers and used regular floor joists to support the loads. Paint to taste for the smoothest sweeping. Some spaces you might choose for your shop might some day need to be something else. Unless this is your permanent shop, start your design for normal usage and you won't have to backtrack later.
Some municipalities require electrical circuitry in pro woodshops be dust-proof.
Typically this utilizes EMT conduit, compression box connectors and weathertight boxes. This type of circuitry is easy to add after the drywall goes on, you can sometimes add a new circuit within existing conduit, and the expensive parts like boxes and recepticles can be re-used in a new location should it become necessary. From my own experience, the setting-up process ends rather abruptly when active woodworking takes over. Get as much done as you can in the beginning. That last coat of paint is much easier to apply without a lot of powertools laying about.