Nursery rhymes are great, because little babies love poetry, they have an instinctive feel of the rhyme and it help them to keep it later in life. My little one loved listening to poems since about 2 months. However I found traditional nursery rhymes pretty "negative" sometimes when you think about it,
, just take a "Rockabye baby" for example. I got Christian Mother Goose Big Book, -- it is beautiful, my daughter likes it very much and poems have a very positive message, I would recommend it...
Also other short classical poems.