I've got a car-radio sized kit built around one of those superb VIA EPIA Mini-ITX boards. This was a hobby-job rather than a task with a specific aim, but possible uses for it would now include:
Sat-Nav & entertainment box in the car.
Voice/email portal in the car - GPRS/Wi-Fi connectivity.
Just about anything else I probably shouldn't be doing while driving.
In the home: it would make a great lounge-box, I guess - all that oomph and connectivity.
Home office: NAS appliance (I like this one - three USB ports, so just hang extra drives off it as required)
In short, it's now a very small and reasonably powerful "spare" PC. But not over-powered - the VIA C3 1GHz CPU and reasonable but limit graphics, so I doubt I'll be installing Vista or using it as a gaming console, although it's well up to playing DVDs. Oh yeah it also has VGA, S-VHS and composite video-out connections. And proper 5.1 surround output. It's starting to feel like I should add a TV tuner :-)
I also have a 7" touch-screen on the way (if I don't get outbid on eBay LOL). Don't have a specific need in mind for that either, it just seemed to "fit" with the rest of the kit so nicely - I can hardly imagine hooking a keyboard & mouse up to this thing, wherever it is eventually deployed.
So..... which OS should I feed this thing? I have an unused (still sealed!) full XP Home SP2, and it's VERY tempting to just shove that in - makes things dead easy. Also slows things down! I'm not scared of Linux/xBSD either, but the variety of non-mainstream hardware is a bit of a worry.
I'm aware that this is very subjective, so I'm looking for a variety of different opinions. Feel free to have an argument! 100 points each to the five people who really give me something to think about.