I'd go for the cyberbrain in the Ghost in the Shell series. Basically, it's a cybernetic attachment made to the brain that gives everyone's brain the capabilities of smartphones. Just think about that for a second.
You could use a virtual telepathy. In other words you could communicate mind to mind using a wireless connection.
You'd basically have an internal GPS that could sync with others so that you'd never be lost and could always locate people if you needed them.
You'd have instant access to a large repository of information i.e. the internet in your head.
Visuals can basically be connected directly to your optics, in other words you can stream video in your mind.
You can sync with technology and control it with your mind.
Those are things we see done in the show, but the possibilities are endless. Like I said, it's basically like having a smartphone in your head.