Well, poking around a bit just now led me to two articles about the Segway from Dan Bricklin. The opening paragraph of the first article, written before Bricklin had gotten to use a Segway hands on, begins:
Make sure you understand disruptive technologies. Their first incarnations often seem like toys compared to existing technologies. The Segway embodies lots of disruptive technologies. I'm pretty familiar with a previous one: The combination of electronic spreadsheet and the personal computer. The combination was first viewed as a toy compared to "real" computers and financial forecasting tools. It only sold about 10,000 copies in the first 10 months and was barely mentioned in the business press for a couple of years.
Bricklin is understating things a bit when he says he's pretty familiar with spreadsheets--he wrote VisiCalc. If you're interested in the Segway, whether as fan, skeptic or just someone who likes to think about the future, read both of Dan's articles.