I recently traveled to the UK using Virgin Airlines and noticed their innovation for speeding up check-in.
Most airlines only allow you to get a ticket using a self-service kiosk if you have no luggage to check in. Virgin Airlines on the other hand *only* allows you to get a ticket via a self-service kiosk. Then, If you have luggage to check in, you take your ticket and luggage to an attendant who takes your bag.
The nice thing about this approach is that the self-service kiosks absorb all the burden of actually producing a ticket. This frees attendants up for the focused task of accepting luggage for check in.