When my son was about two, I used to sit down with him at the computer and bring up the songs I thought his toddler ears might especially enjoy, typically ones I liked a lot as a small child. (Not that I remember toddlerhood. But I do remember being four, five, et cetera, and I remember the songs I especially enjoyed. Most of them were from the 1950s and 1960s.) One song I tried out was "Baby, Now That I've Found You."
Upon clicking once on a link, though, I found myself watching the Alison Krauss version. I watched it once with Sam, mainly because he seemed a little interested, and then found the Foundations version. He didn't care at all for that one, but over the next few months, whenever he caught me sitting at the laptop, would say, "Baby song. Listen baby song."
I'm pretty slow, but I did figure out that "baby song" meant this song, and for about a year it was the boy's favorite and the one we'd listen to together most often. I think my son prefers Krauss's soothing and slow arrangement, making the song actually sound like a song sung to a baby, rather than to a lover.