I heard this song on the way in this AM and was reminded of what a great pop tune it is. You also gotta love the way Madonna sung back then—maybe she still does (I recall someone describing her voice as Minnie Mouse on helium). Anyway, I thoroughly enjoyed hearing this again—see if you feel the same.
[BTW, there seems to be a non-random number of musical theorists who visit OTE. One thing I find unique and great about this tune is all the inverted chords—there are all these great chords where the bass is not playing the root but the third (I think). Bach does that all the time—Madonna, less so, but it really works here.]