There's a relatively good guide for this in the comments at D3DB:
NEW TRISTRAM, Tashun the Miner (first vendor you see).
He sells: Axe, Sword, Gloves, Boots, Chest, Waist, Legs and Shield.
NEW TRISTRAM, Arghus the Collector.
He sells: Wand and Bracers.
NEW TRISTRAM, Radek the Fence.
He sells: Bow, 2-Hand Crossbow, 1-Hand Crossbow and Ring.
HIDDEN CAMP, Silmak the Fence.
He sells: Quiver, Fist Weapon, Helm, Shoulders and Neck.
CALDEUM BAZAAR, Tilnan the Collector.
He sells: Dye, Staff, Spear, Mojo, Magic Source (Known as Wizard Source) and Ceremonial Dagger.
CALDEUM BAZAAR, Lugo the Miner.
He sells: Dagger and Mace.
CALDEUM BAZAAR, Squirt the Peddler.
She sells: Daibo and Polearm.
DAHLGUR OASIS, in the Rotting Cellar, Javad the Merchant.
He sells: Spirit Stone
THE KEEP DEPTHS LEVEL 1, Ironsmith Aldonado.
He sells: Mighty Weapon.
Note that Javad the Merchant won't always have Spirit Stones. The Wandering Tinker merchant occasionally has them. Vendel the Armorsmith usually (but not always) has them.
I think that this guide found an amulet at Silmak the Fence (Neck). Amulets and Rings are on the jewelry tab rather than the armor tab. Squirt the Peddler is also in the Hidden Camp now.