The Devouring (Book # 1)
However! I haven't read these books but I'm told that they're quite scary and they give you the heebie-jeebies in which case the UK covers hit their mark. The cover for book 1 is downright creepy and I wouldn't want to be looking at that thing while reading by myself at night. I actually like both covers but I might have to give my vote to UK on this one for the creep-out factor that seems to be more in-tuned with the storyline.
I have to give my vote to US! The other one is awesome creepy BUT...I really like the style of the US covers. I love their simplicity and I really like the smokey effect of each cover. The other covers are too "childish" for me. (Even though I actually do like the creepiness of it, lol)