Rogues:
Mongoose Elixirs
Arcane Protection Potions
Stam/Agy Food Buff
GFPP's

Warriors:
Same as Rogues

Hunters:
Mongoose Elixirs
GFPP's
Thorium Arrows
A few Demonic runes and Mana pots

Mages:
Greater Arcane Elixirs
Elixir of Frost Power
Int food
GFPP's

Warlocks:
Greater Arcane Elixirs
Elixir of Shadow power
Int Food GFPP's

Healers:
Major Mana pots for bosses
Demonic/Dark runes
Mp5 Food