As I've mentioned previously, I've come into a lot of Hero 4e books (and one 5e book). Currently I own, or am awaiting the arrival of:
Hero 4e core (×2)
Cyber Hero
Fantasy Hero
Fantasy Hero Companion
Fantasy Hero Companion II
Hero System Bestiary
Horror Hero
Ninja Hero
Pulp Hero
What other 4e books or 5e books are must haves? I'm considering picking up Star Hero for the sake of being complete (it's my least favorite genre book, really) and, possibly, Tuala Morn. What else should I take a look at?