Oh, maverick! Kubla Kahn is nearly my favorite!
William Blake's intro. to Songs of Innocence is first, though: it just rings with joy!

Introduction

Piping down the valleys wild,
Piping songs of pleasant glee,
On a cloud I saw a child,
And he laughing said to me:

``Pipe a song about a Lamb!''
So I piped with merry chear.
``Piper, pipe that song again;''
So I piped: he wept to hear.

``Drop thy pipe, thy happy pipe;
Sing thy songs of happy chear:''
So I sung the same again,
While he wept with joy to hear.

``Piper, sit thee down and write
In a book, that all may read.''
So he vanish'd from my sight,
And I pluck'd a hollow reed,

And I made a rural pen,
And I stain'd the water clear,
And I wrote my happy songs,
Every child may joy to hear.