A listing of portable digital audio players that support Ogg Vorbis can be found on the Xiph.org Wiki:  Portable Players for Vorbis

The same wiki also provides a listing of other hardware devices such as set-top boxes for home theaters and car audio systems:  Static Players for Vorbis

We plan to integrate some of this information into OggWatch in the coming months.  We'll also be doing some hands-on hardware reviews of some of these devices.  Check back soon!