If you are going to leave the buffet there, then no floor-to-ceiling draperies. It also see what looks like a floor heater (hot-water heat circulator), which would also limit the use of floor-to-ceiling draperies. Your venetian blinds are nice, but rather spartan. Maybe you need a large painting on each side of the window instead of drapes.

The buffet looks lonely in that space. Is it possible to get another to place next to it?

If you could see the whole room plus how your living areas are decorated, we might be able to suggest something to spark up this space.

Rent or Own?

We own. I fully intend on replacing all the furniture, including the buffet; most likely a longer one. The blinds were just installed and they sent the wrong cover plate. There is an air conditioner vent near the floor. Should I do drapes between each window or just on each side?

Plantation shutters would look beautiful on your windows. Or, because your buffet isn't as wide as the windows, you could put floor to ceiling drapes that are stacked off to each side, with or without matchstick roller blinds or roman shades inside mounted on each of the windows.

I would consider removing the chair rail before deciding about window treatments since it also complicates the decision. Here is roughly what you've got in terms of the windows themselves except I lost the vent in the erasing.

What style is the house overall?

In general the options have included:

1. Top of the window or slightly above, to the floor. In this case I would only do fixed panels on the end.

2. Ceiling to floor. Also would only do panels on the end.

3. Top of window to sill. These would also have to cover part of the window because if they go to the sill you don't want the width to extend past the sill. These you could open and close.

4. Top of window to top of chair rail. These could be wider so they did not cover part of the window since they would be "anchored" by the chair rail. These you could open and close.

The current orthodoxy is that only the first one is correct, and there is something or other wrong with the other options, mostly that it is old fashioned or dated, but I think that depends on the style of the curtain you want, what the style of the furniture is where it is going to be in front of the window, whether you want them to open and close or not and things like that. The only thing I would say you don't want to do is put separate panels for all three windows or put something that doesn't hang right because furniture or things get in the way