My favorite tracks are actually in the expanded OST. Most notably:
Instrument Of Your Liberation
Bar Shootout
Do You Feel In Charge? (probably my favorite of the bunch, it sets the scene so well, when you hear this track throughout the film you Bane has arrived)
I voted for Why Do We Fall? with Gotham's Reckoning and Rise, but really it's the latter two that grip me whenever I listen to the soundtrack. The former, which I believe is Bane's theme (correct me if I'm wrong) with its sturm und drang and 5/4 timing (you know shit's goin' down when it's in 5/4), really conveys Bane even when I'm not watching the film. It arises the "protect yourself" instincts.
Rises is on the opposite end of the scale, particularly the latter half of the track. It is the end montage music to The Dark Knight, and its reuse is practically guaranteed to stir up many emotions that were provoked during the aforementioned sequence. Additionally, Rises' montage is equally emotional, and the combination of that, the music reuse the plus Begins reference in the Rises end montage (you know what I mean) makes it seem like the whole trilogy is there in one sequence. Incredibly moving work by Zimmer, Nolan et al.
Prologue
The Truth About Harvey Dent
Nothing Out There For Me
Blake Visits Wayne Manor
Gotham Is Yours
Without A Rope
On Thin Ice - Batman Returns
All Out War
Chasing The Convoy East
A Hero Can Be Anyone - Rise
Music Trailer 3
And Imagine the Fire and The Shadows Betray You from the official one