Sticking your finger with a lancet will be a thing of the past. Non-invasive sensing will be a relatively near-term reality.
One technology being developed at MIT is Raman spectroscopy, which uses infra-red light as a measurement collector. Read more about it here: http://web.mit.edu/newsoffice/2010/glucose-monitor-0809.html
Another technology being developed at the University of Washington utilizes nanoscale antennas, radios and light sources embedded into contact lenses that can monitor body chemistry through the surface of the eye. Read more about it here: http://www.dailypress.com/health/sns-health-contact-lens-monitors-health,0,49949.story