So far what I have gathered:
Medical items to the doctor in NCR
Small guns ammo, junk, knives and hammers to Dusty's Cantina in NCR
Small guns ammo and Armors to the armorer in Adytum
Guns, ammo, knives and shit go in Gecko, can't remember merchant specifics.
The man near the entrance in San Francisco buys small guns, their ammo and small energy cells.
Gordon at gas station buys meds and melee weapons (inc. Ripper and Power Fist).
