Another way that I was thinking of it is to put the different songs on a linear passage of time as we understand it. Each time you jump to another song or timeloop, you veer off of the timeline at a certain "line/loop" contact point (the Losties in 2007), you travel around the loop to live out the alternate timeloop past (1977 to present), and then eventually return via time passing to your original departure point once again (2007). In this way you could at the same time have a known past from your original timeline, and then veer into your "secondary past" (the one that Miles says hasn't happened to you yet which is why you don't remember it), and eventually "meet yourself" back in the future. What you will remember from there on is something that I haven't examined yet. For instance, would you have two pasts to remember now? Why not?!
Well, I'm not hanging my hopes on this theory at all, it's just something that I'm playing with until I understand what Miles said a little better, in respect to the theories that TPTB have thrown out at us thus far. Feel free to pick up your BB guns and shoot holes in it where necessary. :-)
Update: Wiki says this about Time Loops: "A time loop or temporal loop is a common plot device in science fiction (especially in universes where time travel is commonplace) in which time runs normally for a set period (usually a day or a few hours) but then skips back like a broken record. When the time loop "resets", the memories of most characters are reset (i.e. they forget all that happened)." http://en.wikipedia.org/wiki/Time_loop
Another very interesting source for theories is here: http://www.time-loops.net/nostradamus/Theories.htm