I've been a huge fan of The Hunger Games' US cover since I first read the book. On the other hand, I can't say I'm much of a fan of the UK take. It's a little bit crowded for me. However, I really like the UK's font—it has that edgy look to it. Overall, I think my biggest issue with the UK cover is the loss of the mockingjay symbol—I adore that book-to-cover tie-in.
Let me know if you prefer the US cover like myself, or if you think the UK has it right!