So many of my favorites have already been mentioned.

But this one, by Neal & Leandra, is my current #1:

Old Love
Neal & Leandra

We've got an old love
One we never will get tired of
One that fits us like an old glove
One to warm a winter days
We don't have to say I love you
Quite as often as we used to
Old love just goes without saying,
But we'll still say it anyway

I met we you beneath the willow
You were young, a little shy
But we would sit and talk for hours
Watch the river flowing by
You would laugh at all my stories
And then at dusk I'd walk you home
Who'd have guessed we'd walk a lifetime
Growing up and growning old

We've got an old love
One we never will get tired of
One that fits us like an old glove
One to warm a winter days
We don't have to say I love you
Quite as often as we used to
Old love just goes without saying,
But we'll still say it anyway

We may not leave this town we live in
Life's not as easy as we planned
I always meant to give you diamonds
But you still wear a plain gold band
That old river keeps on rolling
We don't know just what's in store
But in spite of all of this
I don't love you like I did
I love you so much more

And we've got an old love
One we never will get tired of
One that fits us like an old glove
One to warm a winter days
We don't have to say I love you
Quite as often as we used to
Old love just goes without saying,
But we'll still say it anyway
^^