My recommendation is not to use curtains at all. I suggest a fabric roman shade, or a woven wood shade as options, and you may like to add a decorative valance above. Most likely the valance would be mounted on a board, not hanging from a pole of any sort. A photo that shows more of the room would be helpful in providing a more detailed suggestion.

The room is usually used as a playroom so I'm concerned about long cords with little kids, but I see what you're saying. I'll think about that some more. I already have some Marimekko fabric I'd like to use...
The room is in disarray due to a pipe leak. We've pulled up all the carpet and will later paint or finish the concrete. We also took down most of the Sheetrock because we have to replace all of the copper pipes for the baseboard heat.
Ah, the joys of home ownership.

It depends if they are going to be opened or closed most of the time. I would only use curtains if they will be closed all of the time. I'd raise the height of the rod and use full length curtains to give the look of a higher ceiling and bigger window. Otherwise I wouldn't do curtains. I'd do a woven wood roman shade.