Sorry for bringing it up too early. How long do you guys normally wait until you start discussing episodes in depth?
On Gandalf, I don't know what the books said about where wizards came from. But I rewatched LOTR, the Twin Towers just the other night. The part where Gandalf was describing how he killed the Balrog and Gandalf said he died and the movie showed him whisked off into space floating around where he lay dormant, and time had no meaning, blah, blah, blah. So maybe they are following that concept in the movie, and they decided in rings to have them reappear by coming back to earth in a meteor. The movies were criticized for deviating from the books. That thought came to me anyways.
Also, everyone is assuming it's Gandalf still and largely because the old gray guy repeated Gandalf's statement of "when in doubt, follow your nose" at the end. That's a pretty obvious quote but it's not yet for sure.
edit...see some of this already has been covered.