Slow guitar rock-folk ballad - about making the most of now, because "here come the rest of our lives". A song about nostalgia.
Other songs like this:
Time of my life - David Cook
Similar to Best Days in a power-ballad style. This song is about making the most of the moment and enjoying success to the fullest.
Restless Farewell - Bob Dylan
In this song Bob is looking back over a long life - a retrospective I Did It My Way - and accepts the choices made, for better or worse.
Good Riddance (Time Of Your Life) - Green Day This acoustic rock ballad, with contemplative lyrics, was originally written as a break-up song, but was famously used in the last Seinfeld episode in 1998. The lyrics are not specific to a romantic break-up, and perfectly capture the feel of a bittersweet end of a journey.
Just Breathe - Pearl Jam This is lovely contemplative folk rock goodbye song. The lyrics may seem about someone's goodbye before they die, however it can strike a chord with anyone who will find a loved one leaving to be devastating. A comforting song.