9) Dangerous and mysterious and balanced.
For chromatic dragons, I swapped the mental stats so that Red Dragons were huge, powerful idiots, and White dragons were smaller, weaker geniuses who could cast spells no one in the world had ever heard of. Blue dragons are arrogant but honorable, green dragons exist pretty much as written, and black dragons are almost as smart as the whites, and lurk out there in the swamps planning their next victory.
For metallic dragons, I did some stat-swapping and gave them more specializations. Silver dragons, as per all the books, are master shapeshifters. Brass dragons are kings of the sky (bonus to AC while in the air, and gets Good maneuverability at all age categories, while dropping down one from the listed size). Bronze dragons are the kings of breath weapons (they take the damage of the gold and combine it with the ability to shape it and do metamagic feats on it), Copper dragons are the masters of magic (Best spell progression), and Gold dragons are, while not as intelligent as the rest, the most powerful melee combatants in the world. (DR equal to (1/2 Age)/-, and free Weapon Focus and Specialization on all natural weapons.)
In my campaign, any dragon egg can hatch as any color or metal -- while in the egg, the dragon takes tests that determine its color. Chromatic dragons are said to have failed some important test. Metallic dragons are certainly GOOD, but not necessarily nice, and are dealing with threats that most PCs have never even heard of. Consequently, they will still destroy a village or tear a bunch of PCs to ribbons if the PCs get snippity or ignore requests to leave.
-Takyris