The M.E. Accent

So the movie is being filmed in New Zealand...

What kind of accent will the actors go for for each of the characters? As a citizen of the U.S., I'm not all that familiar with most of the actors. Am I to understand that most of them are from the U.K.? Can anybody give me some perspective on which characters might sound like what, and why (for example, I can't imagine Aragorn speaking aught but the King's English)?

P.S.: If ANY of the major characters speaks American English (Frodo from the U.S.'s deep south: "Ahm sa very tahrd, Sam...ken ah set fer a spell?"), I may spew popcorn all over the person sitting in front of me in the theater (re?). Anyone see "Robin Hood: Prince of Thieves?" I love Costner for his baseball flicks, but I almost walked out on that one. It would have been better if he hadn't tried... :P