No Idea Where Will Live - What should we put on the registry?

I would think with either option you would still need kitchen items (pots, pans, plates, utensils), towels, sheets, and small appliances. You could always start with basics and add more items once you figure out your living situation.

I would probably avoid really large items like a bed frame because either the guest is going to have to find a way to bring that in to a reception, or mail/ship it to you. I agree with PPs that no matter what you will need dishes, pots and pans, cups, silverware, kitchen linens. You may have some stuff right now but it will be nice to have a cohesive set of everything. You could also look for a bedding set and bathroom set/towels. A roomba or vaccuum (or both!) are a great idea for a larger ticket item. If you do not register for a lot, people will also just give cash or gift cards which you may find more useful later, so you could keep your registry small and have a card box.

I would put things you'll need regardless of your home. Like you'll always need a vacuum (we have a robot vacuum & still have a standup vacuum so we had both on our registry), you'll always need plates/cups/flatware, you'll always need blankets & nice bath towels, you'll (probably) always need a blender, food processor, serving utensils, etc. Smaller things like trash cans you can always buy when you move in.