They have four at the time of writing: White Stripes, De Stijl, White Blood Cells, and Elephant. I, personally, would recommend to get White Blood Cells first, because it's not so much a blues based record as the one before it, or such a mixed-bag as the record following it.

Elephant was indeed recorded on 8-track tape machines, and also mixed to quarter-inch 2-track tape. It sounds a bit more polished, I believe, because Elephant was recorded in something like ten days while White Blood Cells was layed down entirely in three.