Hunky Dory or The Rise and Fall of Ziggy Stardust and the Spiders from Mars or Diamond Dogs = prefer 70s Bowie. I know it's not really an "album" but Bowie live at the Beeb is amazing! Great tracks live!
Underground was another classic. He was great in the film as Gerald the Goblin Mister. His finest acting role.
Tin Machine 2 was really the pinnacle. Just when you thought he couldn't improve on the first Tin Machine record - wooooooft. Of his early stuff, "The Laughing Gnome" is pretty much perfect.
I actually though his best performance was in The Man Who Fell To Earth although essentially he was just playing himself at that point in time.
His best 3 albums are Hunky Dory, The man Who Sold The World and Low. His best single by far was The Laughing Gnome. Old Dave hasn't done bad for an Anthony Newley impersonator.