I had a very hard time choosing between 1982, 1989, and 1990 (and 1996 if I limit it to the Left Bank). I ended choosing 1990, but it was by an incredibly narrow margin over 1989.
The highs of 1982 are extraordinary, but I give the edge to 1989 and 1990 because there are several top chateaux that I think were making better wine by the end of the decade than were in 1982, such as Pichon Baron, Montrose, and Leoville-Poyferre. I’ve also had more excellent inexpensive 1989s and 1990s than 1982s.
The choice between 1989 and 1989 is much harder. Cheval Blanc, Ausone, Lafite, Margaux, and Latour were much stronger in 1990, Haut Brion and La Mission HB were better in 1989 but the 1990s were still outstanding, and Mouton wasn’t even close to First Growth quality in either vintage so the First Growth edge goes to 1990.
Looking a notch below, I prefer 1989 Montrose, Palmer, and Pichon Lalande to their 1990 versions. On the other hand, I give the edge to all three Leovilles in 1990, along with Certan de May, L’Evangile, Gruaud, Ducru, Pape Clement, and Beausejour-Duffeau. Lynch Bages, Rausan-Segla, and Pichon Baron are toss ups, as are Angelus, Clinet, Fleur de Gay, and La Conseillante. Moving down the ladder a little more, I prefer 1989 Clerc Milon and Meyney, but 1990 Lagrange and GPL. La Dominique is a toss up. Finally, I’ve had more random inexpensive 1990s turn out to surprisingly lovely than 1989s, so that pushes 1990 to the win.