[chrispenycate]

The two stars (and everything else in the system, for that matter) would be rotating round the centre of gravity of the system (more or less the centre of gravity of the two stars.
If the stars are of aproximately equal mass, the centre would be roughly halfway between them, and a stable planetary orbit in the inner space is highly unlikely, so habitable planets would be a good distance further out.
If they are of wildly different masses, the centre of gravity woud be more or less within the larger star, and inhabitable planets could form inside or outside the orbit of the smaller star (imagine Jupiter in fusion, with its moons a secondary planetary system. If the smaller star were cool enough, you could have a second planet in the system inhabitable by the same organisms.
Of course, we won't know the probability of all this till someone goes to have a good long look.

The problem with moons around moons is long term stability; peturbation from the mother planet, from the primary, from other moons, will tend to make Lagrange points, trojan points the final resting place, rather than nice epicycles,