@scotteq: lindylex is suggesting "$300.00 USD a processor" (not for the mobo), witch is OK in my opinion.
At around $320, INTEL, Xeon E5410 Quad-Core Processor (2.33GHz, LGA771, 1333MHz FSB, 12MB L2 cache, EM64T EIST VT XD, 80W, 45nm) is a great choice for 3D applications and video editing. You can also get the XEON E5405 (same, but with 2.0GHz) for about $260-$270.
And to point to your question, there are some good DP XEON motherboards from Intel, SuperMicro and Tyan. In order to be compatible with the 5400 XEON line, it must feature an Intel 5400 (Seaburg) chipset. Here are a couple of recommendations:
■ SUPERMICRO, X7DWA-N, LGA771 /2, Intel® 5400, 1600MHz FSB, DDR2-800 ECC FB 64GB /8, PCIe x16 /2, SATA 3.0 Gbit/s RAID 5 /6, HDA, GbLAN, FW /2, EATX - this one is my personal choice, because it supports more RAM, PCI-X and it's more towards the server stream; also not as expensive as the Skulltrail motherboard.
■ INTEL, D5400XS (Skulltrail), LGA771 /2, Intel® 5400, 1600MHz FSB, DDR2-800 ECC FB 8GB /4, PCIe x16 SLI CF /4, SATA 3.0 Gbit/s RAID 5 /6, HDA, GbLAN, FW /2, EATX - this has the advantage 4 PCI-E x16 expansion slots, but I can hardly believe you're installing SLI or similar to a graphics workstation - you should get a single solid professional video interface, unless you really have money to spend on two of these (as they can easily pass the $1k segment)
■TYAN, Tempest i5400PW (S5397AG2NRF), Intel® 5400, 1600MHz FSB, DDR2-800 ECC FB 128GB /16, PCIe x16 /2, SATA 3.0 Gbit/s RAID 5 /6, VGA, GbLAN /3, FW /2, EATX – another good option, since it offers both PCI-E and PCI-X along with a huge capacity of 128MB of RAM.
These are some of the suggestions, so you may search some other based on these. You said that you would prefer a motherboard w/out integrated audio – that’s hard to find, since integrated ‘HD’ audio chips are so cheap that every manufacturer implement them by default. If you’ll install your own audio interface (and I’m sure you will), you can easily disable the integrated one from BIOS.
Cheers,
Mihail.