I've been reading Eugene Peterson's The Message and got to the book of Isaiah. In his intro to the book, Peterson has some really delightful things to say on the topic of holiness:
The more hours we spend pondering the words of Isaiah, the more the word "holy" changes in our understanding. If "holy" was ever a pious, pastel-tinted word in our vocabularies, the Isaiah-preaching quickly turns it into something blazing. Holiness is the most attractive quality, the most intense experience we ever get of sheer life--authentic, firsthand living, not life looked at and enjoyed from a distance. We find ourselves in on the operation of God himself, not talking about them or reading about them. Holiness is a furnace that transforms the men and women who enter it. "Holy, Holy, Holy" is not needlepoint. It is the banner of a revolution, the revolution.