Picking the best primary key + numbering system

Question

We are trying to come up with a numbering system for the asset system that we are creating, there has been a few heated discussions on this topic in the office so I decided

Answer 1

Don't put meaning into your PK fields unless...

• It is 100% completely impossible that the value will never change and that

• No two people would ever reasonably
  argue about which value should be
  used for a particular row.

Go with option one and format the value in the app to look like option two or three when it is displayed.