I've actually spent far too much time thinking about a set of statistics that was balanced and interesting. It kind of plays with the universe I've made up, but you and anyone else who wants are free to use it and/or alter it.
Body
Strength
Endurance - Affects stamina (Or energy), health, and pain threshold.
Size - Acts like Strength and Endurance combined (With a smaller effect); influences stealth and dodging.
Mind
Dexterity - General accuracy when performing tasks.
Speed - Determines reaction speed and a variety of physical tasks.
Intelligence - Affects experience gain, willpower, energy levels, and a wide variety of skills and abilities.
Soul
Power - A person's magical muscle, determining magical strength and capacity.
Spirit (Or Heart) - A person's self determination, creativity, luck, divine grace, and general drive to do what he or she does. Affects social skills, and gives bonuses to almost everything (Especially magic). Acts like charisma and self-will.
Instinct - A person's ability to focus on survival. Affects perception, and gives bonuses to all on-the-fly skills, such as combat and reaction. Higher levels may give preemptive feelings similar to a sixth sense.
It's designed so that a fighter won't go 100% Strength and Endurance - He might dip into intelligence to gain experience faster, or Instinct to apply a round bonus to all of his combat skills. I think it's important to have attributes that affect all or most skills, and having skills that rely on at least two attributes. Acrobatics, for example, would rely on both Dexterity and Speed, since you have to be able to maneuver your body accurately and get it into place in time to perform certain stunts.
The 3 divisions with 3 subdivisions is just because I like the number 3. You can take out, combine, or change whatever you like, though.