There seems to be four major expressions for hit points.
Low: 10+Con Starting HP, 4 HP per level, 6+Con Surges per day.
Medium: 12+Con Starting HP, 5 HP per level, 6 or 7+Con Surges per day.
High: 14 or 15+Con Starting HP, 6 HP per level, 8 9 or 10+Con Surges per day.
Very High: 17+Con Starting HP, 7 HP per level, 9+Con Surges per day.
Low is mostly used with controllers (Wizard, Psion, Invoker) but also with the Assassin (striker).
Medium is used the with majority of Strikers (Rogue, Ranger, Sorcerer, Monk, Warlock) all Leaders (Cleric, Artificer, Runepriest, Bard, Warlord, Shaman, Ardent), and some Controllers (Druid, Seeker).
High is used mostly for Defenders (Paladin, Fighter, Swordmage, Battlemind) as well as for some strikers (Barbarian, Avenger).
Very High is used only for the Warden (defender).