+1 to what Solo said.
AC becomes meaningless at later levels, as other defenses (flying, Displacement, etc.) move to the forefront. When a monster has a +50 to melee attacks, an AC of 50 does you slightly more good than an AC of 10. Gloves of Dexterity can easily help you hit the +3 Max Dex Bonus of mithral full plate, if you're planning for the long run.
Con is useful for any class, as it improves both your HP and your Fort save. Best of all, if you increase it to an even number later on, the extra HP are applied retroactively.