That’s easy: Peter Jones, as The Book in the original version of The Hitchhiker’s Guide to the Galaxy. However, that’s really a recording of a radio play rather than an audiobook …
If we’re going for pure audiobooks, then my children loved Miranda Harcourt’s narrations of the Horrid Henry books. She did a great job with all the character voices, just like when she played Queen Elizabeth in Blackadder II.
As for real audiobooks for adults … I’m not a big audiobook listener, so I don’t have a favourite narrator, although I will admit to preferring British narrators over American (but that would only work where the characters are British).
I have come across a couple of narrators I haven’t enjoyed, usually because their monotone narrations.
I like narrators who can act well enough that I can hear the difference between the characters, rather than having to guess who is the point of view character in each successive scene. It’s hard to like a book if I don’t like the narration.
So I don’t really have an answer to this question.
