Golly this is a strong round.
As much as I'm currently obsessed with "Walking on the Sky", I've got to vote for "Fortress". It almost rivals "Blackbird" as one of Alter Bridge's crowning achievements. The melodies, the musicianship, the four-part dueling guitar solo... it's Alter Bridge at their best. "Island of Fools" is close for me as well – so heavy and powerful.
"White Knuckles" is a classic as well, especially live. I was lucky enough to see its live debut in 2007 at the Underground in London before
Blackbird came out. My only thought was, "what the fuck just happened?!" Myles apologized and said something like, "sorry, that's a lot of notes."
"Coeur d'Alene" is probably somewhat underrated as far as
AB III goes. One of the more innovative tracks on the album, and a standout main riff. "Save Me" is probably the most basic song Alter Bridge have ever written. I like it, but it definitely falls short of the others here. One thing I noticed while listening to it just now: compared to Mark's more recent guitar work, the verse riff is quite loose and the palm mutes seem kinda random – it's almost like Mark was just learning how to gallop!
Ranked:
Fortress
Walking on the Sky
Island of Fools
White Knuckles
Coeur d'Alene
Save Me