Proxmox should work fine on ANY motherboard with a Z77 chipset.
We have tested it extensively on several Intel and ASUS motherboards with H67, Q67, Z68 and Q77 chipsets, Core i5-2500K, i7-2600 and i7-3770 processors, with 8, 16, 24 and 32 GB of RAM. All configurations worked fine.
There are two problems that we encountered:
Adaptec / ASUS BIOS problem
ASUS motherboards permanently lose their memory and processor overclock function when a modern Adaptec RAID controller (in our case the 6805E) is plugged into them, so we have to run our ASUS P8Q77 / i7-3770 setup with DDR3-1333 instead of (the otherwise fully supported) DDR3-1600. The Adaptec controller also killed an ASUS Z68 motherboard. Apart from that issue, the controller works fine.
Q77 remote installation problem
If you plan to install Proxmox from a remotely mounted DVD image via Intel AMT, the installation will take a VERY long time (about 1 hour), filling the screen with SATA errors. Fortunately the installs completed successfully every time, but if you are in a hurry use a local DVD drive. This happened on both ASUS and Intel boards, so we suspect it's a Debian issue on the Q77 vPro chipset.