Mentioned by Tim above, my favorite closing song is Parting Song, composed by Dave Weber in 1993 in memory of John Purdy of Torquay.

Soon the morning sun will rise and dawn will bathe the sky,
There's time for just this parting song before we say goodbye;
So sing together one and all and raise a glass of wine,
Here's hoping we shall meet again along the road of time.

We've shared our stories, yours and mine, we've shared our hopes and fears,
In memories of distant youth, we've both rolled back the years;
So sing together one and all and raise a glass of wine,
Here's hoping we shall meet again along the road of time.

The ever-turning fateful wheel must cause our ways to part,
And bringing untold mysteries, another day will start;
So sing together one and all and raise a glass of wine,
Here's hoping we shall meet again along the road of time.

So from endings come beginnings, from the old shall come the new,
With hope for tomorrow, we'll see the parting through;
So sing together one and all and raise a glass of wine,
Here's hoping we shall meet again along the road of time.

The melody is very beautiful, and the only recording of it I know of (aside from the YouTube video Tim linked to) is on Old Songs & Bothy Ballads (Fifesing 4) - Nick-knack on the Waa, a CD of traditional folk songs. This album also has one of my favorite (and largely unknown) traditional Scottish songs The Gallant Forty Twa (not the more famous song of the same name).