My vote goes to Rust in Piece.
I like Megadeth's first 6 albums but Rust is bottom place. (As a whole entity I must add, because it has a few songs I truly like "Take No Prisoners" and "Poison Was the Cure")
But I'll always be a Peace Sells maniac.
I don't care much about post '94 Deth though.

Slayer -

I enjoy all the other 80's albums & SITA over Reign in Blood.

Samael - Worship Him

I admit I haven't fully delved into their last few albums other than a cursory listen, but I'm positive I'd choose to listen to them all day over this. I've tried to like it and I'm not fully averse to "primitive" on occasion, but I guess I don't have that much attraction to pain to withstand this.

I'M THE GUY THAT LOVES "Heartwork" THE MOST!!!

I still remember hearing on of the songs on a free compilation, and going, what is this?

Chaos AD

I really loved Sepultura until that filth, the album that broke all the selling records and was pumped to the sky by the incessant MTV adverts.

And what about the rest of the catalogue? I wouldn't say it's that unusual to prefer those albums over Reign in Blood - after all, they are all highly regarded, and it's often cited as one of the best runs in metal. But if you prefer the likes of Repentless, God Hates Us All and Diabolus in Musica over it as well, that'd be more note worthy (all that said, this isn't the only example of this sort of thing in the thread, so sorry if you think I'm picking on you).

Is “Worship” generally considered to be their most popular or best? Not sure I’d heard that very often.

Depends on whether we're talking MA popularity or general public poularity. Because they're two very different things.

I think there has to be a certain amount of leeway with the question. Best-selling albums aren't necessarily those held in highest esteem by particular cross-sections of fans, of which there are many. Both are different but equally valid forms of popularity.

Are You Dead Yet? is my least favorite Children of Bodom album

In This Moment.
All their newer stuff is their most popular, basically when they went into the Blood and beyond phase. To me, their work on Beautiful Tragedy and The Dream were their absolute best and I wish they would have kept that sound and aesthetic.

Measuring the popularity of a work is difficult, I myself when creating this thread have had doubts about my examples because to a certain extent they are subjective. Earlier Morbert mentioned how he doesn't know anyone IRL that Heartwork is his favourite Carcass album and how that honour is held by Necrotism or Symphonies. But I've come to the conclusion by looking at various general media, such as Spotify, RYM, Last.FM and this own site, as well as individual opinions that Heartwork is the most popular. And yet that doesn't necessarily mean it's the favourite album of many fans.

No problem at all!

To answer your question, I've never really delved into the albums after Diabolus in Musica. Been meaning to for years but have yet to get around to it. In retrospect maybe this wasn't a great contribution to the thread (for the reasons you mentioned), but I wanted to participate and couldn't think of a better example.

Side point - DIM isn't great but "Bitter Peace" ranks up there as one of my favorite Slayer songs.

Bitter Peace was always one of my favorite Slayer songs too haha

Deceased - Fearless Undead Machines. It's grown on me over time. Especially lately. But I still prefer the stdio albums before and after it.