The current state of GNU/Hurd when it comes to hardware support is that the kernel is i686 capable, there is a ported Linux 2.6.32 drivers layer for network adapters, basic support for IDE / SCSI / PCMCIA / Xorg, and Xen PV DomU support. Among the major lacking features though is no support at all right now for USB, sound, and Serial ATA drives.
When it comes to software support that's compatible with Richard Stallman's kernel, it's considered "quite stable", the OS can run for quite a while before needing any reboots (there are some memory leaks remaining), about 78% of the Debian archive builds out of the tree, there is a Debian GNU/Hurd installation CD, there will be unofficial Debian "Wheezy" CDs with the Hurd kernel, and there is a Nix-based distribution that uses the Hurd kernel.
The KVM / Xen support is deemed as "not satisfactory, even if good support" and the DDE layer for device drivers will continue to leverage Linux drivers but still needs to be maintained and more code needs to be ported from the Linux kernel.
Future work being planned by Hurd developers includes doing the actual Debian GNU/Hurd Wheezy release, providing Xen PVH support, write a Serial ATA (SATA) driver, x86_64/64-bit support, language bindings support for translators, read-ahead capabilities, HDD/Sound/USB support, and a possible official Debian GNU/Hurd release in time for the "Jessie" release that will succeed Wheezy.
The status update and bits of future plans for the Hurd micro-kernel were shared last weekend at FOSDEM 2013 in a presentation by Samuel Thibault. Slides for the presentation with more information about Hurd can be found here (PDF). For more details on the Hurd version of Debian, read Test Driving GNU Hurd, With Benchmarks Against Linux.