I'm sure this has been asked millions of times, but hey, let's make it a million and one.
Everyone should know mine by now...but if not...it's
Red Rover!!
This song speaks to my heart and soul like ISA. I think about the death of my grandfather when I hear it.

This one makes me tear up. The guitars are amazing and there are certain notes in it that KILL me. I NEVER get sick of hearing it and it's one of those songs that I stop what I'm doing and just LISTEN to it....intently.