Can someone recommend a good book on the aesthetics of visual graphics and web design?

I’m a good php programmer and i know photoshop, after effects and flash and am a decent graphic designer technically but frankly i feel i am missing some training in standard design practice. Can someone point me to a good book or tutorial or author who covers the art of of graphic design from a purely visual perspective? I don’t need a programming how to, I know them, i need guidance in style, colors, layers, depth, shadow, mood, font usage, good use of different effects, etc.