I am playing a Juju Oracle 4 / Necromancer 3 / Mystic Theurge 6 / Agent of the Grave 5.
While neverending hordes are a fun concept, it's tiring on the table, so I want to have the least in number, but most powerful undead minions I can raise.
I have Undead Master, Spell Perfection (Animate Dead) & Spell Specialization (Animate Dead) & Mage's Tattoo (Necromancy), and I have an orange ioun stone and Magical Knack (Oracle), so as an Oracle my Animate Dead is at Caster level 20 and as a Wizard it is Caster level 13.
As an Oracle, I can control up to 156 HD.
As a Wizard, I can control up to 52 HD.
My Command Undead are 7 HD (Oracle) and 3 HD (Wizard), so I don't believe they are worth mentioning, but oh well :P
So, what are the most powerful undead I can raise and permanently control?