I loved these too. Even though he also wrote seriously good horror novels, it was the Hyperion books that first drew me to him. (If I remember correctly, it's been a long time.)
I'm definitely gonna have to check out his horror novels now. I read Ilium and Olympos years ago, and they were decent novels (on a list to read them again and review), but they didn't seem to have the gravitas or the complexity that these two have.