mastodon

I like Crack The Skye, but it's a bit too proggy imo. I definitely prefer Leviathan & Blood Mountain.
 
Crack the Skye pretty much got me into Mastodon, too. I enjoyed it a lot, so I went and picked up Leviathan, which I like even more.

Crack the Skye is definitely not the album of the year, though. It's simply a solid album.