Buttons*
Glass half Panda'd
I'd have to disagree with UnTheist, Paul. I personally don't like Lateralus all too much. My favorite is Aenima. It's an album that I can genuinely say every song on there is a great song. It seems to me that most Tool fans either like Aenima best or Lateralus. So I'd say pick up either of those two. Or...why not both?
I think it depends on what you're looking for in an album! Lateralus is extremely progressive. It's one of those albums that you listen to the whole way through to get the experience of it, versus the lyrics you can sing to. (Though everyone knows that the song Lateralus is a Tool fan's must)
Aenima has songs that are easier to sing and dance along with... dont take quite as long to get to the point, and they're extremely well done. I believe the energy is higher and therefore more attractive to more people.
In either case... get both man, you're missing out if you dont
Wings -- ToOl
(This is one of my top 5 favorite TOOL songs)