Not to hijack the thread but because it is about spine design, jforbush picked up a very interesting knife called the Groove Master at Knob Creek (if I see another one next time, I'm gonna buy it). Here's a picture courtesy of the BusseCollector site:


The spine is designed so that it's comfortable to use the first notch for your thumb, or the second if you want to hold the knife with you index finger along the top of the blade. It looks a bit odd, but is quite comfortable to use.