I recommend:
Fifty-One Tales by Lord Dunsany. This is a collection of very short prose poetry by one of the greatest authors of the 20th Century. I think older children (and smart and sensitive, which I'm sure yours are) would love the evocative language and clever twists. There is a lot of Greek mythology woven into these imaginative and melancholy tales.
Nordic Gods and Heroes by Padraic Colum. A rewriting of the Eddas in approachable language. I would have immensely enjoyed being read this as a child of 8.
I think smart/sensitive kids would love them, along with the adult readers. However, they are too difficult for children below the age of reason (the Dunsany being more difficult than the Colum).
But I wouldn't rule any book out on the basis of being a bit difficult, especially not when the sound and substance are wonderful in their own right. My parents read my brother and I The Lord of the Rings when I was 7 or 8, and it is one of my fondest childhood memories, even if - maybe partly because - I didn't understand everything.