Monster collections: Minions Rebirth (I have yet to get Complete), Gaming Frontiers: Monsters, and Book of Templates.
Splatbooks: Forgotten Heroes Paladin, Call of Duty, Beyond Monks (I like the Enchiridion of Mystic Music but there are no bard pcs in our current game). The paladin books really inspired our Paladin PC and the DM into a flurry of creativity in prc and feat creation for our campaign. I'm considering having my eldritch knight multiclass into unfettered from Way of the Sword when he exhausts the EK levels.