I don’t find awning as good for airflow if you need to capture breezes but best to keep direct rain off and winders are easy to use.
Double hung allow heat to escape out top with cool air entering at bottom.
You need to consider access to windows to open them as well.
Sliding aren’t very suitable for narrow windows as you need two panes and frames to go with them.
You may want different things in diff rooms. My kids room have one double hung and one awning with the awning window on the exposed wall weather wise. This is the one that gets opened regularly as it is easier for them and we r in Melb. Top opening can be good if tucked a bit under an eave to stop rain getting in while letting out hot air

Add energy efficiency to your list. The right choice for your climate zone, which you don't specify, will save you money while living there and enhance resale value. Make sure the builder installs correctly and doesn't cut corners with insulating around the edges compromising the benefits, too common. In general swinging is supposed to be better than sliding but I'm not up-to-date with all styles and manufacturers so there might be new innovations. You might have specific reasons to choose a window prioritising a particular advantage for a particular room. Remember flyscreens, I've seen questions about that after the house is built and it can be difficult to solve at that stage.

https://www.yourhome.gov.au/passive-design/glazing

Thanks @Kate & @macyjean!

Forgot to state my climate - it's in Melbourne (same as you Kate).

Yeah I think I'm leaning towards awnings at the moment for most (protection from the rain is probably the selling point). Although I'm wondering for the gym - might want more air flow - which type of window gives the best air flow? There are about 3 windows in that area which are about 1.8m wide by 1.5m (but split 2, side by side). Currently 1 section is fixed, and the other is and awning. But I wonder if it's better to have casement or something else to get more air flow in....

I would recommend going to a Dowell showroom and looking at their windows. Our builder wanted to use dowell windows in our extension, however when we looked at the quality of the double hung windows we really wanted, we were very disappointed and chose to go with another company.

Sliding to allow full opening
But need to consider range of factors what is outside. Is there eaves for shelter.