My impressions:
For fighter-types, Masters of Arms is one of my all time favorite books. It is ALL about feats and classes specializing in different weapon types/style. But it has some interesting spins on this. Want a demon who specializes in using it's telekenisis? It's in there. Or how about a character who has honed their mastery of magical trinkets like the immovable rod to an art. Way less bland than the "weapon master."
Green Ronin has some good selections. Their witch, shaman, and unholy warrior books are all good, as are most of their race books. Their assassin book and Secret College of Necromancy are a bit shaky.
Quint books are hit or miss. I would agree druid is not the strongest book. However, I really liked Wizard, Sorcerer, Rogue, and Monk.
Speaking of Monks, Beyond Monks by chainmail bikini games is nice. The martial artist is a bit close to the monk for my taste, but I blame that on the monk for being too narrow of a core class. Still, if you don't use the martial artist class, it still has a bevy of useful feats and PrCs for monks and other characters.
The path series has already been mentioned. My two favorites of these books are the Path of the Sword and Path of Faith. The series in general is pretty good if PrCs in what you are looking for, and if you (like me) think you don't have to be 20th level to be epic, legendary classes are a great concept (though I feel that of the four books, path of magic's legendary classes are the least appealing.) On the not so bright side, all of these books have "schools" that trade feat like powers for XP with no real good explanation for why they aren't feats or class abilities. Other than that, the path books vary widely with a variety of supplemental material. I like Sword for its different combat terrain rules (good DM fodder) and I like path of faith for its expanded rules on small gods.
