Images. But MAN this was a lot harder for me than I would have thought it would be. Rust is a fantastic album (although it took me awhile to get into it back in the day).
I also hope WildRanger isn't shocked that this will likely be a landslide in terms of the poll. I mean, this IS a Dream Theater forum, and we are talking about perhaps their most-beloved album. Of course, if we were on a Megadeth forum, I would expect the exact opposite landslide.