That's a good question.
Pretty much every song thats coming to me as I reply to this has a certain level of profoundness.
I can barely think of any non-profound or throwaway U2 song at the minute, although I'm sure there are a couple somewhere along the lines, hmmm maybe 'Big Girls Are Best' can pass as one!
One of my favourite quotes from the main man himself, '...there is blood in our music...'.
I think the main one's that hit me like a brick are...
* Kite
(how moving to see so many people totally reduced to a 'blubbering wreck' including myself on the last tour)
* One
* Tomorrow
* Where The Streets Have No Name
* Beautiful Day
(I'm sure a lot of casual listeners might think its just about the sunshine! Nothing too wrong with that I suppose. I prefer to go with Bono's description of what its about though! Like many of U2's songs it works on many different levels.)
* Mofo
* Stuck In A Moment You Can't Get Out Of
* Wake Up A Dead Man
(from the Achtung Baby demos, despite it being the song that later became The Fly/Ultra Violet/LWTSH, and sung in 'Bongolese', the words that do come through along with the sonically apocalyptic ending have always implied to me that this is another ditty about suicide.)
* Dirty Day
* Acrobat
* Bad
* 40
* Until The End Of The World
* Love Is Blindness
There are so many more too. One or two of the above songs hit such a raw nerve, that I find them slightly difficult to listen to.
City Of Blinding Lights has managed to make me teary-eyed within a couple of listens also, quite an astonishing song. I think all of us U2'ies are in for an amazing year or two once again.