[elvet]

I'm at the point in my familiarity with the genre that I look mostly at the authors. However, there are some book covers that catch my eye, and I find myself picking them up only to find that I've read the blurb before and was not interested. So I can definitely say a good cover attracks me to a book. I'm pretty sure a bad cover would not deter me from an author/title/blurb that interests me, but if I'm on the fence about the book, it may.
Good covers for me - detailed, colorful renderings of landscapes or deisigns.
Bad covers - cheesy musclebound heros with flaxen haired heroines. Any graphic violence or allusion to horror.