As a continuous and complete work, it's my favorite hip hop album ever. The only one I rarely listen to bits and pieces of - when I'm in the mood for it, I'm in the mood for the whole thing, from the tone-setting intro to the amazing melancholy of "Growing Old" (I tend to think of the "Elevators" remix as a bonus track and therefore not part of the album proper, but it's nice too). The production is my favorite of all time and I can't believe it wasn't more influential, or that Organized Noize didn't continue in that vein a little longer. And both MCs are about at the top of their game - they might have gotten a little better and more full of their respective personalities later on, but at that point they merged into this awesome, cohesive whole and yet stimulated different sides of my brain, and brought different things to the table.

Measuring objectively I think "Aquemini" might be a bolder creative statement with higher highs, but "ATLiens" is the best single-album statement I can think of.