If you're looking for a quick fix for your bare naked windows I just stumbled upon a new line of
semi custom, ready made, window valances. They utilize an ingenious curtain rod system that allows you to attach the pre-made fabric components quickly with Velcro that is factory installed on the treatment and the rod.
The fabric selection is limited but there are enough good patterns to choose from to cover the basics.
Check out the Velegance site for a short instructional video on how their system works - It's impressively simple. The treatments and rods are very reasonably priced and look like they would be an easy install for any DIY'er.