My favorite coda in all of music has got to be the one in the first movement of Beethoven's Op.74 "Harp" String Quartet.
When I started listening to this quartet, the thematic structure and motives seemed disjointed and really didn't 'gel' for me through the recapitulation. I'd often stop paying attention before the coda arrived. That all changed on a drive up to Mt. Hood to do a solo hike at Paradise Park. I was listening to this piece on the drive up US-26 from Portland, and as you climb through the final sets of hairpin turns that takes you up to Government Camp, and ultimately the road to Timberline, I hit this view of the massif after coming around one of the rock-cut hairpin turns:
At that moment the coda's furioso on the violin had been joined by the opening theme in extended half-time on the 2nd violin and viola, and at that moment, I had a vision of the lifecycle of the mountain and the surrounding forests, from the volcanic birth and subsequent eruptions and building of the shield, through multiple ice-ages and cycles of dormancy, extinction and ultimate erosion of the massif and re-assertion of the old growth forest below. The beauty of that cycle, of all the cycles of birth and death everywhere became apparent to me through the music and I began to weep as I was driving up there to experience it. It was magical.
The YouTube musicologist Richard Atkinson provides a great 2 minute analysis of this coda. Well worth a listen:
The shift in this song by Xinlisupreme from low-key black metal wash to an explosion of transcendental noise around the 5 minute mark makes my cock go off
Speak Now Or Forever Hold Your Peace, by my man Terry Reid (also covered by Cheap Trick on their first album). Coda begins around 3:50 but you should probably listen to the whole song because it's great: