Thrax

He avoids what I call the 'People in Fursuits' syndrome, which is to write 'animal ficiton' simply personifying the animals as acting like humans. Adams has the characters acting on realistic concerns and non-human perspectives, translated into human language. I can't even really think of any other animal characters in any fiction that springs to mind as much as Adams'. King has some in his stuff, like Oy in DT or the dog in Insomnia, both those are just memorable portrayals from a human perspective.

Have you read "Creatures of Light and Darkness"? Or the short story (well, technically a novelette I guess) "Unicorn Variation"? Both good reads, I found them in the library here. I also was able to read the rest of Richard Adam's stuff here. None of it is as good as "Watership Down", but "Shardik" comes fairly close. "The Plague Dogs" is also a good read if a bit heavy handed with the allegory.

<agrees with previous poster, adding "Dreams in the Witch House" and "The Colour Out of Space" as faves> Also, Neil Gaiman's novels are pretty enjoyable.