O.k. so this thread hardly got any attention at all so I thought I'd give it a bump to the front page so maybe people will actually post in it this time (Especially since the book covers were just released).
So, here are my theories on what's going on in the two different versions of the cover:
Judging by the UK one, Harry, Ron, and Hermione all look like they're being sucked into something, or falling into something because they look like theyre trying to hold on. Judging by the way Harrys posiitioned, he's reaching for something, and I'd say he's reaching for a horcrux (possibly the cup). On the back of Harry, you can see a house elf holding on. I think its Kreacher because Harry inherited him and because assuming RAB was Regulus Black, Kreacher would be a lot of help to Harry being his former houseelf. Also, Kreacher is holding a sword which judging by the red ruby is Gryffindors. Where they are, I don't know, but I'm assuming because of all the gold, it's Gringotts. We heard no one who tries to rob a vault can make it out alive and we heard Dragons are down there guarding high security ones so I think that's what they're going to have to get past.
Ron and Hermione are in fancy robes and Harry is not, indicating they were somewhere where they needed to be dressed up while Harry wasn't so... possibly a funeral seems the most logical choice, but then why wouldn't Harry go? I don't know what else it could be unless they were on a date or something.
On the back of the UK book shows Hogwarts all white and stuff. Perahps I didn't read the books carefully enough, but I don't think it ever said anywhere Hogwarts was white. So I think the castle may be frozen. Like i think its frozen in a coat of ice, and that's why all that mist is around it. I think thats because the castle was shut down so it might have frozen itself over to stand the test of time until its reopen again.And i think the only reason the lights are on inside is because Dumbledore said "Help will always be given at Hogwarts to those who ask for it" so if somebody needed to get in, the casttle would let them in. So i think it shows the trio will be going back there at some point (obviously to talk to Dumbledore's portrait).
Then the inside flaps...one of them shows a snake in an orb, and I have no idea why its in there. I'm pretty sure its Nagini, but why would it be in an orb? Maybe its a spell or some kind that Harry, Ron, or Hermione cast on it, because I think at some point they're going to be learning all of Dumbledore's spells and stuff to aid them, so maybe thats one he knew?
The other flap shows Harrys Patronus, meaning i guess Prongs is going to end up saving him again. But I don't think it will be from a Dementor this time.
The US cover shows Harry and Voldemort together in some sort of ampitheatre, but its odd because they're on top of ruins and neither of them has a wand drawn which is REALLY odd, but might be to avoid the Priori Incantatem effect again, but its still really od.
They're both looking up in the air at something and judging by their looks i'd say Voldemort is trying to summon something and Harrys trying to intercept it. What it could be, I don't know. It could be a horcrux, a wand, etc. I think its probably the last horcrux or something.
There are also shadowy people all around them in the ampitheatre but they dont look like death eaters so I dont know who they would be BUT.....there are curtains on either side of them so like maybe Harry and Voldemort are beyond the veil...and the shadowy people are the souls of the dead or w/e was said to lurk beyond there.
And what is VERY interesting about that cover is.......Harry DOESNT HAVE A SCAR. This is odd because on every other book a point was made of showing the scar so it looks like Harry may lose it somehow. I'm thinking the scar was the physical evidence that a bit of Voldemorts soul was in him, so when he extricated it from himself the scar disapeared.
Also I don't know if it has any connection, but the hole the trio seemed to be falling out of/getting sucked into, inside of it is the same colors as the sky in ampitheatre where Harry and Voldemort are fighting. Maybe they're getting sucked in or falling out of there?