Lullabye Little One by Dianne Ochiltree, illustrated by Hideko Takahashi. This was actually the first book Abby ever got off the shelf and brought to me to read to her. We received it a few months ago as part of the Dolly Parton's Imagination Library (I'll write a post about this amazing program another day).
This book tells about a child's basic bedtime routine in a fun, rhyming story. There are only a couple of sentences per page, and the illustrations are very simple, warm, and peaceful. I've read it so many times I actually have it memorized, and one evening I even recited it to Abby while we got her ready for bed. ("lullaby, lullaby, put blocks away -- lullaby, lullaby, all done! hurray!") She loved it!
It is definitely our current go-to book at bedtime right now, and Abby will also bring it to me any other time of day to read. :) Our only trouble is that it is a "real" book (not a boardbook), so for a 13-month-old, the pages are getting wrinkled and Abby did rip one of them the other day (scotch tape to the rescue!).