Q: How do you call a mythical bull-person with a NH2-group attached to it?
A: An aminotaur!
Minotaurs, Large monstrous humanoids with 6 RHD, have high strength, moderate constitution, and average to bad other stats. They're capable of wielding weapons in their hands while attacking with their horns, making them an obvious choice for melee characters. Powerful Charge only reinforces this role by making their natural attack even stronger on charges.
The cow-beasts have one other ability worth mentioning. In an utter perversion of its origin myths, they are immune to mazes magical and mundane, can't get lost, and don't ever get caught flat-footed. The ability may also give them the ability to track creatures without the feat: ask your DM how it works.
I think a +0 LA is defendable here: minotaurs are a strong melee chassis with enough added abilities to make them a viable choice amongst the alternatives.
Next are mohrgs!