For the cafe jukebox, we could have something like:
NAS box http://www.ebuyer.com/product/248760
2 1TB disks http://www.ebuyer.com/product/319639
A/V over CAT5* http://www.ebuyer.com/product/156212
USB DVD drive http://www.ebuyer.com/product/180608
(total ~255 quid)
and I will throw in my netbook (so I can buy an Ultrabook).
You can have the netbook in the kitchen, ethernet into the router, audio and video into the A/V over CAT5 transmitter, run some CAT5 over to the projector and sound desk, and connect them up to the A/V over CAT5 receiver. The NAS box (mirrored disks) can be somewhere, mounted as a network drive, so that the netbook can access the content. CDs can be ripped using the external drive, and DVDs can even be played through to the projector.
* CAT5 is network cable