Well, the classical ideal of being well dressed involves colors, patterns and textures that complement and contrast each other. Think of it as a conversation.
I know Isaia lookbooks have a rep for being over-the-top, but it depends on who's styling them. For ex, check the last picture from the F/W 2012:
See how the shirt and tie relate to the purples and browns in the suit, even though the shirt has a blue ground. See how much more lively and interesting it is than a solid white shirt a white square and navy tie would be. There is a conversation, but it's not loud at all.