I thought I'd post a link to this:
http://blog.makezine.com/archive/2011/02/why-the-arduino-won-and-why-its-here-to-stay.html
I agree with most of it, and think Arduino has a defined a very good model.
Unfortunately, the author either hasn't done as much as I have with Arduino's, or he has been much luckier. The FTDI Serial driver does not 'just work' on all platforms. We had horrific problems a few weeks ago with a couple of Windows laptops at DEV8D, and I have had problems with Windows laptops at most public event I've been involved in.
I had hope the Arduino UNO had fixed everything, but it hasn't.
I do not think Arduino is the end of evolution :-)