A wearable server/computer. To tie together the wearable projects, something with a decent amount of processing power, able to handle things like speech recognition, etc.
The easy way would be something Raspberry Pi powered.
But something I think would be nice is making use of an old smartphone I already have, it is probably on-par or more powerful then a Raspberry Pi and Linux can be run in a chroot container.
Plus it has a screen built in, although the touch screen functionality is broken.