Interestingly enough, to me at least, reading voice is also important. I tend to have very specific voices in my head when reading dialogue. For example, I recently read the first two books by Will Adams, The Alexander Cipher and The Exodus Quest. His stories center around the adventures of British archeologist Daniel Knox. When Knox speaks, I hear a very refined and brave Orlando Bloom in my head. Think Legolas or Balian rather than Paris. Weird? Maybe. But I could give hundreds of more examples of other characters, too.
I was just wondering if most people have a similar experience, or if they simply hear variations of their own voice?