Today's monster is a mid-level undead with a paralysis ability and too many HD. Sounds familiar, doesn't it?
A mummy's 8 undead HD are partially compensated by its 24 strength. They also have wisdom and charisma bonuses, in addition to an impressive amount of natural armor for what's essentially a dried-out corpse. DR 5/- doesn't hurt either. Less great are the 20 ft. movement speed and fire vulnerability.
Mummies have two further special abilities. Mummy Rot isn't awful for a disease: the short incubation time may mean it's actually relevant within a battle, and its effects are severe enough to matter should infected foes escape. It's still a disease, though.
Despair is much better: the first time a day something spots you, it must make a saving throw or be paralyzed for several rounds, no actions on your part needed. It may make visiting towns awkward, but in combat it's quite nice. Fear immunity may or may not work here.
That said, I think mummies deserve +0 LA. Their reasonable chassis is made considerably better by Despair, and they should be able to keep up with a normal party.
Nagas are next!