This is where I stand with Metallica these days.
Never really cared for KEA. I generally don't like the whole Judas Priest-esque "motorcycles and headbanging and leather!" brand of metal, and KEA feels too close to that for me to be able to get into it.
Of the three other 80s albums, since I first heard them 15 odd years ago, I've always ranked them Justice/Puppets/Ride. I've been through a big dip in my interest in Metallica until lately, which means I've listened to them fuck all in a long time. Returning to them, although a lot of Justice has a special place for me still, I can't help but feel Ride is the better album. Their 80s albums undeniably became more clinical and calculated as they went, so Ride just seems the most natural and impassioned. Masters is now waaay down the bottom. Little of that album interests me much at all, and I really don't understand why.
Black Album, Load, Garage and S&M are mixed bags - some amazing stuff, some okay stuff, some shite. I have no interest in Reload beyond a few tracks.
I remain a staunch defender of St. Anger and Lulu. In fact, before the recent re-spiking in my Metallica listening, these were the only albums of theirs I was putting on. If you don't like them, cool, whatever, there are a few tracks on each that don't do it for me, but I love the majority of both albums.
Death Magnetic was weak pandering trash. I was appalled by it when it came out, and have never revisited it. For all the stuff of theirs I'm not a fan of, I really respect the fact that Metallica have always tried different stuff out and gone wherever they feel like going. DM felt like an almost complete violation of that spirit.