For me, the deepest songs on a personal level are "Like You," "Hello," and "My Immortal," because they remind me of my Grandma, whom I was very close to.
On another personal level, "Bring Me To Life" is deep to me. I told a friend of mine once that song an video reminded me of our friendship. I was an emo little 13-year-old who didn't have many friends, and he was always there for me (and still is). I was never sure if he realized how much he meant to me, until I told him that about the video and he said, "Except I wouldn't let go."
"Lithium" is also pretty deep for me because I definitely see the battle within myself in that song - knowing sadness for so long that you don't know who you'd be without it, but wanting to let it go and be happy at the same time, so you're trying to find some sort of balance between those two extremes.
I also like "Tourniquet" because...well, all I can really say is been there, done that. Having that battle inside too, something else I know too well about.
All of their songs are deep, but those are the most emotional for me, I think. Of course, all of their songs are emotional for me on some level.
