Check out my colleague, Rohit Bhargava's post Visual search . It's from his blog on Influential Interactive Marketing. The visual interface has been explored in so many great ways and I am thrilled to see it in a search interface.
Here are some of my favorite non-search visual interfaces:
The Smart Money Market Map - how old is this? I remember it over 5 years ago...
And now, we have local search from MSN that lets you overlay businesses onto a local map. Check out the ice cream stores I never knew I had: ice cream in 20912. Some results will feature satellite images from their TerraServer site.