I'd go with any epia board. I personally use the epia m10000 with the m1-atx PSU. I hope to put LinuxBIOS on it soon. As for shutdown/suspend I plan on implementing a LinuxBIOS+Grub-Fast-Boot+Tuxonice resume from hibernate. This should be a very fast boot up system.
I really want to experiment around with the pico-itx boards by via. Yeah, I know that via+Linux support isn't that great, and I hope they open their eyes soon to Linux. If we make our voices loud enough, I'm sure they'll listen.