This is a nice little thread, right here. UnforgettableLemon, I run into you all over the place, 'round these parts.
Anyway, I have to say that I have never ever been able to listen to U2 while trying to drift off to sleep. I do think that, in theory, most of your suggestions are pretty much spot-on accurate, but I've never been able to listen to U2 and sleep: even with the Passengers' album, I'm just too connected to the music. I can't doze off, because I can't ever get my head outta' the songs.
I'll make this quick, here, cuz it's a bit off-topic...but it does fit.
In the Spring of 2001, after I had already forsaken U2's last effort, I was still spinning At The Drive-In's effort from 2000 (Relationship of Command ) with alarming regularity. My ex-fiance' and I were then in a long-distance stage of our relationship, and for some insane reason she decided to listen to THAT album, one night, while trying to fall asleep. Now, if anyone has listened to that album, he or she surely recognizes the error in thinking this way. We were both very into the band at that time, and it just helped her to feel closer to me; towards the end of the album, though, there is a rather sinister sound bite which opens a song with audio of a phone call between what sounds like a political rebel threatening disaster if his ransom demands are not met to a terrified woman on the other end of the line. She was in a half-state of sleep while listening to this, and she nearly died with fright when she woke up hearing it and not knowing what ominous man was with her, in her room...! Of course, it was just her music....
I always loved that story...
Sorry for ranting...!
Seriously, I'm considering rocking my kids to sleep to this song, when I have them..
thats the worst part of falling asleep to zooropa with headphones on.
that version. 
