Smashing Magazine has a round up of the latest thinking on and prototypes for new user interfaces. Some feel way out there (along with rocket boots and meals in pill form) others closer to home.
For me, the more successful interfaces these days are the ones that minimise the role of the device – that quite literally narrow the gap between the user and the information they need. Adaptive Path's Aurora interface, part of an initiative by Mozilla Labs, does this quite well in the way it uses relative size and perspective/depth to show the most appropriate information. However, the stacking of information around the frame and the new selection tool feel too rooted in the old desktop and mouse metaphor to really move things forward. Take a look at the demo:
More interesting to me is the bookmarking and history concept – also on the Mozilla page. The inclusion of context elements to jog your memory is inspired and the timeline design is very pretty.