Recessed lighting like downlights to do the basic buy essential job of lighting up the space and perhaps pendants above areas that you would never walk through e.g. above the dining table / island bench

Looking at the first below I'd say, to be on the safe side, the bedhead should show half to three quarters above your tallest pillow. The second photo I believe shows too much bedhead.

Thank you for the ideas. The windows are actually new and double glazed so are well insulated. I do need the block out for light though. I like the idea of starting at the top, I wasn’t sure if I should start middle or top. I bought those rollers not long ago but they’re too bright white so they might have to go. If I can go with just a curtain and blockout that would be good. Thank you.

Agree with Siriuskey above. Hard to decide without seeing the style and layout of the house. If the expense of 3m windows is prohibitive, stick with the 2.7m ones and go for the 3m ceilings in the larger spaces. Install curtains at ceiling height so when drawn, it has the perception of full height windows and gives you nice simple lines. See below. Smaller spaces like powder rooms and studies perhaps you could have lower ceilings but that doesn't always save any money but small tall spaces need to be treated differently with the decor. Also heating in winter in Melbourne will have an impact on your energy bills. Heat rises so having low down heat like in slab heating will make the space more comfortable for the dollar spent. Think about fans in winter to bring the heat back down as well as for cooling in summer. Are all the downstairs spaces flat ceilings? I.e, no double height or sloping ceiling spaces? The amount of light in a space doesn't only depend on how high the windows are. Sun shines downward and so having windows go down to the floor and spread across floors may have more impact on light levels. This depends on where you place furnishings, what floor coverings you have etc. In bedrooms for instance where there may not be great views and you want to maintain privacy, I often prefer to have narrow tall windows carefully placed rather than the typical developer wide high sill windows centrally located on the outside wall. Are you on a suburban or urban site of in the country? That will impact privacy vs views. How much overhang or screening will you have to prevent summer overheating? If someone is designing this house for you, they should deal with all these issues with you. My feeling is there is much more complexity to consider than just your one query. Share your plan and elevations for us to help you more, even if they are just sketches. Good luck, C.