The two sets of US covers are very similar, yes. I think the second set with the expanded gates is newer. Those are the covers I have, so I personally prefer them. The only major difference is Dimitri's presence on the third cover.
The first covers are so close to identical to the US covers, except for the swirly black backgrounds. The red UK covers may be my personal favorites, because I'm just a sucker for covers with emblems or symbols on them. Particularly like the snowflake on the Frostbite cover.
The German covers definitely have a darker feel to them. St Vladimir's looks like Count Dracula's castle in the background there. They're alright, though.
Tsk, tsk. When will these Swedish cover designers learn: you can't transpose the same image of a girl's face onto all three books in a series, change the colors around a little bit, and call it a unique design? (See the Swedish covers for the Hunger Games.)
I kind of like these covers... but don't really see what most of them have to do with Vampire Academy. Maybe it's been too long since I read the first few books, but I don't remember any butterflies or girls with swords facing down very friendly white wolves. Ah, well, at least they're eye-catching.
Reminiscent of the US covers... I like the computerized look of the model, for some reason. The pose on the third book is an odd one, but the other two seem to work. Meh.
Well, this girl doesn't resemble Rose, nor Lissa. And what's with the bat tattoo?... I thought Rose had marks on the back of her neck for each of her Strigoi kills. Now that would make a cool cover for Blood Promise, the fourth book: the Strigoi marks tattooed into the back of a girl's neck.
Gee, I didn't realize Dimitri was Edward Cullen's long-lost, Russian brother. They blatantly switched models for him, too. And Lissa's (??) eyes on the first cover are weirdly sunken in. She looks like a Buffy vamp with her game face on. Not really a fan of these.
The manga art style on Japanese covers is something I'm personally always a sucker for... but here Rose and Lissa look about eight and half Dimitri's height. Oddly enough, anime Dimitri is closer to how I imagined him. Except for, you know, the whole manga-ized thing. I think these covers could have been a lot better.
So, that's 32 covers from 9 different countries. I did find several more international covers for the Vampire Academy series which I didn't include due to how long this post was getting. If you want to check out the Dutch and Italian editions, you can at Goodreads.com -- that's where I get 80% of these covers. Hope you guys enjoyed looking at all the VA covers, and as always, let me know what you think!