The original live version of "Tonight, Tonight, Tonight" was the peak of Genesis, in my opinion. I am a fan of all the many eras of Genesis, but my first favorite era was the mid-'80s.
This song and it's arrangement is powerful, ethereal, atmospheric, and even a bit gratuitous, sort of emblematic of the 1980's and its MTV driven consumerism and ambition. Phil's voice was still fully intact, allowing for the original aggressive delivery of the lyrics, and the song to retain its original key, as well as Tony Banks's mysterious sounding synth keyboard bridge, none of which would ever be repeated in subsequent live tours.