Having used both ArchLinux and Ubuntu, I can\'t think of any current hardware issues. When I used Ubuntu 10.10, the USB 3.0 driver caused issues suspending, but it works fine now with Ubuntu 12.04 and Arch.
CPU: AMD Athlon II x4 640 3.0 GHz
Cool \'n Quiet: Scales the frequency as expected.
SB/NB: AMD 880G/AMD SB710
RAM: 12GB 1333 MHz DDR3 (2x2GB, 2x4GB)
SATA: I\'ve used it in both IDE and AHCI modes; they both work.
USB 2.0: Works.
USB 3.0: Works.
GPU: Onboard ATI Radeon HD 4250 is functional but has pitiful 3D performance with the Radeon driver, but, with Catalyst for Linux, it works as well as can be expected. I use a discrete GPU in any case.
LAN: Realtek RTL8168B, works.
I have used WOL some, it works.
Sound: Intel HDA, I\'ve tested the green stereo output, red microphone input, blue line in, and front panel headphone and microphone ports. I think it\'s safe to assume the others work too.
PS2: Works, but only one port.