Here's a good one I found via the NewPages blog. Bob Harris wrote a stupendous blog post about overused words in book reviewing. I think this should apply to book blurbs, too. Of course, there are many more than seven overused words and phrases in ye olde booke reviewing, so readers have added liberally in the comments section. It's a fine post. Take a look.
Here are some words/phrases I would not mind never reading in a review or on a book cover again, even despite having used some of them myself. I vow to never write these words again in a review without being sarcastic while using them, in which case I probably should not use them:
Sentences so sharp they cut the eye.