Well.... I found X Japan in 2002 when I was 18 years old and 3-4 years I thought they were the best band in the world.
In the beginning my favorite album was Blue Blood and it still is a great album in it's own way because of the songs. No one can deny that most of their best songs are on it. When I got more into the band and hearing different kind of live versions of songs, Blue Blood just didn't sound as good anymore. The mixing is pretty fucked up on that album and the several live versions of those songs just sound a lot better or simply are just faster than the originals. Only songs that I like better on the album than live are Endless Rain, Orgasm and Unfinished.
Later Vanishing vision was my favorite. It was a great album all the time but at some point it just felt the best one.
The sounds were really raw and you could feel the energy and aggressiviness (is that a word?) of a young band. I just loved it and to be honest it's still a pretty good album, though I wish for a better mixing.
Also Dahlia was amazing in my opinion. It never was my favorite but equal favorite with Blue Blood or Vanishing Vision.
And actually this album is the reason I wanted to give my thought to this topic. I just finished listening to the album and it's pretty crappy and cheesy. For some reason only songs I enjoyed were Scars and Tears. Even Dahlia which was one of my favorites sounded lame. Back in high school I had some friends who also got into X Japan but most of them didn't like Dahlia (the album) and I just couldn't understand why but now I guess I do
Probably the album just hit the teenager emotions I was going through at that time, but today, to be honest I had hard time listening to it completely through. So booooriiiing
So I guess my answer is the album that I haven't mentioned yet which is Jealousy
When I was a huge fan of the band Jealousy was easily my least favorite. It just didn't give the same feelings the others did.
But nowadays when I listen to X Japan every now and then, Jealousy is the easiest to listen to.
It's strange how the opinions change when you older.