A list of all item named sold in shops, this list is also the official Bukkit list, so most Bukkit plugins that allow item spawning can you it.
(Ex: /give diamond_sword 1)
(I removed some unobtainable blocks/items)

If you see something that should be changed on this list please leave a comment.
ALSO notice, this list is not case-sensitive

Blog post: http://www.planetminecraft.com/blog/making-my-34mb-home-into-a-zombie-surival-map/
Server post: http://www.planetminecraft.com/server/the-land-of-gazamo-bukkit-permissions/

Tools:

WOOD_SWORD

WOOD_SPADE

WOOD_PICKAXE

WOOD_AXE

WOOD_HOE

STONE_SWORD

STONE_SPADE

STONE_PICKAXE

STONE_AXE

STONE_HOE

IRON_SWORD

IRON_SPADE

IRON_PICKAXE

IRON_AXE

IRON_HOE

DIAMOND_SWORD

DIAMOND_SPADE

DIAMOND_PICKAXE

DIAMOND_AXE

DIAMOND_HOE

GOLD_SWORD

GOLD_SPADE

GOLD_PICKAXE

GOLD_AXE

GOLD_HOE

Common Blocks:

STONE

DIRT

COBBLESTONE

WOOD

SAND

GRAVEL

LOG

GLASS

Armor:

LEATHER_HELMET

LEATHER_CHESTPLATE

LEATHER_LEGGINGS

LEATHER_BOOTS

IRON_HELMET

IRON_CHESTPLATE

IRON_LEGGINGS

IRON_BOOTS

DIAMOND_HELMET

DIAMOND_CHESTPLATE

DIAMOND_LEGGINGS

DIAMOND_BOOTS

GOLD_HELMET

GOLD_CHESTPLATE

GOLD_LEGGINGS

GOLD_BOOTS

Everything Else in Alphabetical Order!

APPLE

ARROW

BED

BOAT

BONE

BOOK

BOOKSHELF

BOW

BOWL

BREAD

BRICK

BROWN_MUSHROOM

BUCKET

CACTUS

CAKE

CAKE_BLOCK

CHEST

CLAY

CLAY_BALL

CLAY_BRICK

COAL

COBBLESTONE_STAIRS

COMPASS

COOKED_FISH

DIAMOND

DIAMOND_BLOCK

DIODE

DISPENSER

EGG

FEATHER

FENCE

FIRE

FISHING_ROD

FLINT

FURNACE

GLOWSTONE

GLOWSTONE_DUST

GOLD_BLOCK

GOLD_INGOT

GOLD_RECORD

GOLDEN_APPLE

GREEN_RECORD

GRILLED_PORK

INK_SACK

IRON_AXE

IRON_BLOCK

IRON_DOOR

IRON_DOOR_BLOCK