1. The Fragile
2. The Downward Spiral
3. Pretty Hate Machine
4. Hesitation Marks
5. Year Zero
6. With Teeth
7. The Slip
8. Broken
9. Ghosts I-IV
(HM/WT/YZ could easily change around in the next few years, but I think 1-3 and 7-9 are pretty set)