Looks like it's time to retire my iRiver PMP-120...
...because Archos has just released the SDK for their PMA-400 series devices! That's where iRiver failed to meet my expectations, with respect to embracing Linux as their PMP OS.
First idea that comes to mind is an all-in-one, non-linear video editing application. Would be ideal for all this talk of video blogging to replace audio-only podcasting.