With a career as varied as Bowie's, it is all but impossible to pick a favorite album, especially since he's assumed so many guises and toyed with his sound as much as his image. If you are talking about social impact, Ziggy Stardust would be the likely winner. If you're talking about scraunching rock and roll performed with an attitude that transcends mere mortals, then Aladdin Sane might cop the prize. For inventiveness, Low could win. It all depends what you are looking for, but if it is possible to judge Bowie's work objectively (a ridiculous thought, actually) then what album contains the best of all his virtues? Probably Lodger.