Basement HVAC supply location
The short answer is do the most effective of the available option for each room. You may not get them all set up exactly the same.
For most modern basements in Minnesota the supplies are in the ceiling near the windows and the returns are low on an opposing wall. That's the ideal, in my opinion. You get better flow over and around the window with this arrangement since the air can be directed downward, along the window. It's difficult to do that from a wall vent, so condensation and frost build up more readily, and the air near the windows feels colder (and therefore more drafty).
Obviously it's difficult to get a vent below a window on an exterior wall, and you wouldn't want to compromise your insulation and HVAC air temp by doing so anyway.