I don't have an all time favorite, thankfully, but all the speakers I have now are, for some reason or another. Otherwise, I would get rid of them.
Thing is, I forget what the old favorites really sounded like if they aren't still around being played. I ran them into the ground, otherwise, and they were likely suffering from some kind of audible wear for some time by then so, I was usually relieved to replace them.
I like to think that what I am into currently is a culmination of all that past experience and that I have gotten better at this and as such, really would not find myself settling for less now.
I sure had a good time with my more notable speakers of the past but, that was pretty much compared to nothing. . .