I'd have both receptacles installed during the renovation. Then you shouldn't have to call the electrician back to finish the job when you get the new DW.

I've never heard of a 240V residential dishwasher. Commercial units have more issues than just running the 240V to them.

But if you want to do this, you can do either of those.
The other option is just to put in the 120V circuit and use the same wire (with the white-grounded conductor remarked to some other color when it ceases to be the grounded conductor).

Better yet, if you don't know if the new device doesn't also need 120V as well, you could just run three conductors (+ground) and have the ability to run both 240V and 120V at the same time.

Thanks. I believe Miele makes some highly-rated home models that run on 240V. If I bought one of those in the future, I wouldn't need 120V anymore. So could I ask the electrician to run 240V wiring, but just hook it up as 120V for the time being? I could always run 2 circuits up front, but then there would always be a circuit that wasn't being used.

A 120v circuit requires 2 wires (plus ground).
A 240V circuit requires 2 wires (plus ground).
A 120/240v circuit requires 3 wires (plus ground).

So could I ask the electrician to run 240V wiring, but just hook it up as 120V for the time being?
The only difference between a 120v circuit and a 240v circuit is where the wires are terminated at each end.

Check the amperage requirements though. The wire size might be different for the commercial (or high-end residential) dishwasher.

The Miele "Professional" SCVi dishwasher can be had either as 208/240 or as 120. the 240 version requires a four wire hookup however. So I suggest your best option would be to install that (as I suggested).