They (in my case, L.W. Apartments) say no to holes in walls but you know they don’t care as long as you patch when you’re done. Plain and simple, I don’t think I could live with the gorgeous vertical blinds they freely supplied. My solution to the ugliness is to put up some curtain rods and inexpensive curtains.
It seems like “these days” curtains are making ceilings higher and rooms bigger. Try hanging your curtains up a notch or so higher. Don't forget you'll need longer curtains for this technique. Check out these fabulous photos for help.
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Here's a little help from Pottery Barn if you want to know how to hang a drape correctly.