Silvia: http://www.lesliespring.com/page3.html
It's really impressive. The responsiveness seems snappy and accurate and the speech output is not too mechanical. Looks like a nice 21st century version of Eliza... Still a long way to go, but you have to like the prospects of this kind of research meeting up with the latest breakthroughs in robotics at some point in our not-to-distant future...