That could almost start another thread on "best parting songs".

Apart from "Auld Lang Syne" to the usual or older tune:
The Parting Glass (Irish version)
Kind Friends and Companions (Sheila Stewart)
When First We met (Alan Bell)
In Freenship's Name (?trad)
Sae will we Yet (Ok, a refrain rather than a chorus!)
Tak a dram afore ye go (Ian Sinclair)
Parting Song (Dave Webber)
Any more?