Definitely Richard Burton.
I thought about HAL for a few seconds, but I think after a few days, his voice would creep me out.
For some reason, I hear all of H.G.Wells' books as read by Richard Burton, probably because I heard the War Of The Worlds musical before I read the book.
Then, gradually he became the voice of Science Fiction, and unless I heard a character in a book speak before (in a movie, for example) they get gender-specific voices, but with Richard Burton's style of speaking, unless described otherwise.