DON'T do this one. Neither the reset nor the arduino bootloader does not reset the watchdog
That's a bit strong given the fact that it's fairly easy to shut off the watchdog at the top of setup.
But it's not. Depending on the bootload, the arduino spends several seconds flashing the leds in a "healthy" sequence and/or checking for serial traffic to see whether it should upload a new sketch or start the existing one. If you've gotten it to reset by setting a short watchdog timeout and going into a loop, you might never get to the setup in your sketch before the next watchdog reset happens.
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1234876699
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1234338562