westfw:
Well, you can think of using the Due for anything where the Uno does not have enough program space, data space, or pins. You could have used an 8-bit Arduino MEGA instead, but the MEGA is more expensive than the Due...
Here's a little table:Cost IOS Flash Ram Speed
Uno $30 19 32k 2k 16MHz
MEGA $60 70 256k 8k 16MHz
Due $50 70 512k 96k 84Mhz
The Due may also have a full-sized 64/80bit floating point type, which could be handy for some people. And a real D-A converter. Since it's CHEAPER than the closest equiv 8-bit system, the real question is "are there any applications that are unsuitable for a 32bit arduino?" (one that pops up pretty quick is "things requiring 5V IO.)
Wow! The pricing of Atmega2560 is ridiculous. The Due will kill off 2560. However, there is still one area which Atmega2560 wins Due despite its higher price. It is lower power consumption. Running at higher clock speed, the Due has to suffer higher power consumption compared to its 8-bit counterpart. So, for battery-operated applications, Atmega2560 is still worth considering.