I've only really enjoyed eight of the twelve I've bought, so I'll rank those eight.
1. Porcupine Tree- Fear of a Blank Planet
2. Clutch- From Beale Street to Oblivion
3. Type O Negative- Dead Again
4. Pig Destroyer- Phantom Limb
5. Novembers Doom- The Novella Reservoir
6. Devin Townsend- Ziltoid the Omniscient
7. Sonata Arctica- Unia
8. Rush- Snakes & Arrows
Disappointments: Megadeth, Shadows Fall, Men As Trees, and The Hidden Hand.
EDIT: These are so goddamned out of order except for 1 and 2. Who knows what I'll think come January 1st.