I Love You Through and Through is one that I started reading to the babes when they were a few months old. I still read it to them - although it's a little on the simple side - they still request it regularly.
This one is great for helping babies learn their body parts and there's a sweet interactive element. Almost every page has an activity simple enough for a baby to do or for you to do to your baby.
Books are one of my favorite gifts to give. Here's my sweet-boy nephew, Judah, enjoying I Love You Through and Through, from his doting auntie and uncle: