Jo Rowling translated the Swedish version of " Deathly Hallows" to mean the horcruxes. It seems they were having trouble with the translation, so JKR stepped in and basically confirmed or implied that it definitely concerns the horcruxes.
I, for one, am terribly glad to hear that as I most want to follow the trio on this hunt. I remain convinced that Harry will need to get some vital information from somewhere or someone on just how to destroy these vessels of Voldemorts soul. I doubt if Snape is going to lend a hand, but maybe...
I'm also interested in Dracos fate, the two-way mirror as Ataahua mentioned since JKR implied in an interview that we WILL see it again and whether or not Harry will take a trip through Dumbledore's pensieve.
The cover art of Hallows leads me to two things:
Harry has a look of determination and his outstretched hand has his palm facing upwards, while Voldemort looks a tad frightened and has his palm facing outward. Harry looks to be more in control. Also, the UK version looks as though an underground trip into Gringotts may be happening, although it could be anywhere else.
I'm looking forward to being taken out of Hogwarts for this one ( unless Voldemort attacks the school) and being transported to wherever JKR takes me to. I cannot wait to visit Godrics Hollow with the trio early on.