I voted Stone Roses on the basis the debut album was a work of genius that has left an indelible mark on me. The rest churned out some cracking tunes, mind.
Very weak group - three acts which all released just one great album each and a band that made consistently good pop but never achieved greatness. Nirvana as the most groundbreaking.
Never invested much time in The Stranglers. I probably should. Stone Roses - one exceptional album plus around ten further gems. A pretty good return. Nirvana - I have a bee in my bonnet about Nirvana: they (inadvertantly) ruined a potentially interesting music scene and replaced it with guff. However, clearly they had some good tunes, although Nevermind unfortunately uses the same few chords over and over again. The Police: 80s soft rock, but pretty good quality soft rock. Don't mind them. Stone Roses for me.