He's definately had a dive in quality from 1983 onward (Heathen notwithstanding), but that doesn't mean much for someone as powerful as Bowie. His influence is undeniable in the creation of modern pop, everything he does, he does in a signature style that's been mimicked and never imitated. He can be both avant-garde and catchy at the same time, not to mention his staying power. This guy managed to take career-killing risks every few years and come back stronger than ever each time. How can you not at least respect that?