Which X79 Board?

Looks like you have selcted the top three contenders. Have you taken a look at the intel DX79SI.

I just built a new workstation with the Intel and a i73930k. I use my boxes (3) for 3DS Max Design, Vue, Carrera, and of course Adobe CS5. The new one for my primary workstation, the other 2 i7920s for my render farm. Along with playing Battlefield3 and a few other intesive graphics games.

Any board you pick will work fine. A good graphics card will be needed. I use a GTX570 in each box.

If you don't want to overclock and even if you do the Intel is just fine. The intel has a utilty for "safe" or like me lazy overclocking. Got mine up to 4.0GHZ with just a couple of mouse clicks. Frankly don't need the overclock. The system screams on multithreaded applications.

Come to think of it. You really don;t need an x79 platform unless your applications rely heavily on multi threading, such as rendering or animation.

From that list, I would go with the ASUS P9X79 PRO

The ASUS Sabertooth X79 would be another option.

Six $200-$260 LGA 2011 Motherboards, Reviewed might get you a better idea of what's out there.

The p9x79 WS is a good choice!   But as a workstation system for 3d, you want to get a mid ranged board and invest the rest in a higher end gpu!

Asus, Evga, Intel and MSI are among the top makers of high-end Mobos so the prices mainly-depend on the number of SLI/cross fire slots available.

so decide how many GPU/s you want to install and start from there.

For now, only ASUS X79's are reliable and of the MOBO's linked the ASUS P9X79 WS. MSI, Gigabyte but I haven't seen X79 EVGA's have had both temperature and OC'ing issues affecting their MOBO's; Gigabyte's were so problematic the UD5/UD7 lines were pulled from the shelves.

Sparing you a lecture, I'm not one for using a Professional (Workstation) for a glorified Gameboy. If this work is indeed mission critical and e.g. calculating important load requirements or other complex data then you might want to look at the Xeon LGA 2011 E5-2XXX, ECC, a better WS MOBO. Many of the new Xeon LGA 2011 offer 8-cores.

What would you guys think for a 1155 motherboard?

For which CPU? Xeon or consumer Sandy Bridge? Don't forget the SB-E i7-3820 LGA 2011.