It's pretty hard for me to say what soap opera has my favorite opening credits or theme song. I've always loved the theme song for now canceled the NBC/DirecTV soap opera, Passions. I'm also a big fan of the theme song / opening for the now canceled ABC soap opera, All My Children. WhilIe it's not necessarily a "theme song", I've always loved the Days of Our Lives theme song and opening credits. Days of Our Lives is also the first soap opera that I ever watched when I was a kid, and I still watch it now every day on Peacock.
I've also always been a huge fan of the different versions of the opening credits that I've seen over the years for The Bold & The Beautiful. The Bold & The Beautiful definitely has always been my favorite, when it comes to the theme songs and opening credits for CBS' daytime soap operas that I've watched over the years.