Curse Workers by Holly Black:
The only book I own in this series is Red Glove and I have the cover on the left, which is actually my least favourite. Unfortunately for me, even though the matching Black Heart cover is on Goodreads, I can't find it anywhere, so I doubt I'll be able to get a matching series for this one. The middle set is my favourite, but I actually really like the right covers of Red Glove and Black Heart, but I don't like White Cat.
Delirium by Lauren Oliver
I own this one and I have the right version, which is my favourite. Too bad they switched to the middle one. I also think it totally bizarre how the girl in the middle one and the girl in the right one look nothing alike. I haven't read it yet so I can't comment on which matches the book.
Born Wicked by Jessica Spotswood
I definitely prefer the left cover for this one. It's so much more eye-catching. Although it does look as though it could be sort of erotic-y, since her skirt is kind of short and she's lying down. But I like it! There's nothing wrong with the right cover, but it just lacks the magic of the left one.