Any new circuit needs 4-wires, a retrofit can be done with an existing 3-wire circuit (where neutral and ground are connected at the range). All new ones have neutral and ground separate at the range, and all new wiring to it should be that way, too. The size depends on the range, and to a limited degree, the length of the wire. With the length of the run you are considering, length isn't that big a deal so no reason to upgrade it for that. You can use a smaller cb on a larger wire, but can't go the other way. So, you could err on the size of the wire (bigger), and then choose the breaker suggested by the range. Downside is, larger wire costs more. It all depends on the range you choose.
If you are considering a range hood or a combined hood/microwave, or a hood with heating lamps and a big motor, then run another circuit along with the stove's as well.