Oh, my, Essex, what a mishmash of voices!
Peter Woodthorpe's Gollum always made me think of Fagin, so I prefer Andy Serkis's and it's him I hear, now, as I read. John Hurt was not bad at all as Aragorn, but Robert Stephens has such a beautiful voice, I am still hearing him, though Viggo was wonderful. BBC Elrond had a melodious Welsh accent, which suits Tolkien's Elves, but I think Hugo Weaving has taken over in my head. The trouble is, the dignified Elves of LOTR are so very different from the ones in THE HOBBIT, who dance around singing silly songs and talking about finishing off all the cake, you have to do an adjustment between books let alone the film!
If you want to hear yet another Treebeard, get hold of AT DAWN IN RIVENDELL and listen to Christopher Lee ... He sounds like Stephen Thorne (BBC Treebeard) but even better - and he can sing.
So now I'm hearing *him* rumbling, "Hroom hoom" when I read the book and singing to the tunes from AT DAWN...
Sorry - I know the topic was the films. But "contamination" can come from anyh interpretation.