Right now, I think they're all really underrated apart from Thriller. Everyone is buying compilation albums and Thriller it seems.
But generally, I think the media sensationalism and bias caused every album post-Thriller to be underrated, and increasingly so as time went on (irrespective of the quality of the album). In that regard, Invincible has to be the most underrated.
I want to say Invincible... because I remember when it came out the media kinda trashed it.. it does have some songs that make me cringe (Cry anyone???) but mostly pretty solid and his voice is all deep and gravelly which I liked. I mean not every song of course, but he did use his deeper voice more. I will say though that as far as his music goes, overall it wasn't the best album for me, but I think that had more to do with who he chose as producers rather than MJ himself. R. Kelly? Rodney Jerkins? Babyface? Meh for me, all of them. Now that's just my opinion.
Second place goes to BAD just because it could never have lived up to expectations following Thriller. That thing could have been made of SOLID GOLD and folks woulda still found something to complain about.
Dangerous - there isn't a bad song on there!
But Invincible is good too, I can't stand it when the media talk about how much of a 'flop' it is. They always say his music went downhill from Thriller, but really I think Thriller is a touch overrated.
Ima say EVERYTHING besides Thriller..I felt that Off the Wall should've won around 4-5 Grammys instead of the 1 Grammy it got..Bad was just as good as Thriller and Off the Wall..and he should've won some Grammys for that album..I felt he got robbed..HIStory was his most personal album..and I think that album deserved more recognition than it got..Invincible really wasn't that bad..yeah it wasn't his best, but it still was good! Dangerous is a good album because it showed that he could crossover from the 80's into the 90's and the songs on there were good..I think people were too concerned about him matching the success of Thriller and ignored the great substance that his music had..