If you travel frequently in/out of the UK (via Heathrow/Gatwick), and don't always take luggage, then this may be of great interest to you.
Next time you fly, you can submit to an iris scan (well, a photo), which then allows you to use the "Fast Track" lane at border control - where a camera scans your face and eye, rather than the standard queue and passport examination.
When I came back into the country this weekend, there was no queue at the automated terminal - the one chap who I saw use it passed the huge queue which I was trapped in, and in a few seconds was back in the UK. I had to wait another 20 mins to get through.
Of course, I still had to wait for nearly an hour for my bags to show up, but thats a different story!