Visions of purchasing the Asus EEE has grabbed me lately. It would probably be useless for embedded development, but if I imagine myself somewhere on an island (or in a mountain cabin) hacking away at my latest ideas. There wouldn't be much embedded work done there.
At the minimum, embedded work would take a PC, some sort of JTAG interface and a target board (and maybe a power supply). To do embedded I am chained to my house (or the lab/cube at work). With a nice portable, I could be sitting in a coffee shop or in an airport terminal, jamming to tunes while I hack away.
This is a different kind of development, though. As much as the embedded devices I hack during the day will impact people (I design pagers, satellite based trackers, etc), writing pure software (that either runs on a server or someone's PC) has the potential to impact far more people (and hopefully for good, not evil!).