My church uses the Common Lectionary, a selection of readings from the Bible that work through the whole text, pretty much, every three years. Each week we have an Old Testament selection, a New Testament selection from the gospels, and a New Testament selection from the other NT books. The pastor normally incorporates one of these selections into the sermon.
I appreciate the intent of the lectionary. Using a lectionary makes certain that the preacher will not just stick to a few favorite texts, but will have to read, and perhaps preach on, the entire Bible.
Still, as a way of actually teaching the Bible, I think the lectionary is a failure. Three unconnected snippets each week are too short and too many to follow. Since, in my experience, it is a rare preacher who tries to integrate all three each week, most of the readings are not developed at all. And even if the preacher does follow one section - the gospel, most likely - for several weeks, it is very hard to hold on to the thread of preaching. Usually, the sequences of sermons are not connected with one another, and often only loosely connected with the text.
I think we would be better off preaching the Word the way the Reformers did: work through a book, or a theme, thoroughly. This does not mean that today's events and concerns could not be incorporated - on the contrary, nearly all of the Bible ties readily to today. But I, as a listener and student, would rather hear one sustained argument for a season that really explicated and connected a text.
The lectionary, it seems to me, makes most of our Scripture reading in the service into a magical act of just saying the words and hoping they have some effect.