Some songs, like a lot of Relient K songs tend to get in my head so much that I HAVE to listen to them (though it isn't a bad experience when I do). I listen to them so often that I like them. Haha, those songs sort of make you like them. Is that what you mean?
If you haven't heard Relient K, I recommend "Be My Escape", "Which to Bury, Us or the Hatchet", "When I Go Down", and "Devastation and Reform". (I kind of picked them at random, though, haha)
I have such a hard time picking just one song out of all of Skillet's music. Comatose has such beautiful violin sounds in it.
I really like "Better Than Drugs" for some reason. And "Whispers in the Dark" was actually the first hard rock song I had ever heard. XD Have you heard "A Little More"? I also don't know why I like that song so much, but I do.