Atmel AVR
The best thing about the Atmel atmega range of micros is the availability of good free tools, namely AVR-GCC and AVR-LIBC.
dasicarpodoc
DASICARPODOC means "DAve's SImple CAR iPOd DOCk." It is a way to integrate an iPod to a car without a headunit. It displays artist and track information on an LCD and provides simple iPod control via remote buttons.
Ethernut
I've started experimenting with an Ethernut board. Mostly all I've done is alter the supplied sample programs to make a web controlled LCD display.
Development Environment
The tools I use for AVR development:
Ubuntu packages are available for avr-gcc and avr-libc for point-and-click installation of AVR tools using Synaptic.
Or for a manual installation of later versions go to this page for a step by step guide to building the complete GNU toolchain for the AVR target.