If you can get by with 2 instead of 3 graphics cards, a single Ethernet port, 4 memory slots, 6 internal and 2 external SATA connections, and aren’t going to do any overclocking, save yourself (or, since you aren’t overclocking, most likely your company) some money and go with Intel for around $300 (all figures are USD approximation from here on in).
If you want to overclock, dropping another 10 bucks gets you the Gigabyte EX58-UD5. You get dual gig Ethernet, heat-pipes, 2 more memory slots, 4 extra SATA ports, 3-way SLI and crossfire, etc.
The MSI Platinum comes in between the two, sometimes even lower than the Intel Smackover. Depending on exactly how it is priced by your retailers, it might be a good deal. The Gigabyte has a much nicer power system and components, plus a bit more SATA goodness. The MSI Platinum and Eclipse both don’t have the memory slots centered beside the CPU slot, while the other mother boards all do. The different length of the wire traces from one to the other can affect stability at high speed; centered memory slots means symmetrical traces, which are obviously equal in length.
The only big advantage MSI brings to the table is that their memory slots accept 4 GB sticks for a whopping 24 GB total, while ASUS’ slots will only take up to 2 GB for a total of 12 GB. Gigabyte boards can also handle 24 GB, and even if the Smackover takes 4 GB sticks, you can only get three of them in there in triple channel. The Eclipse also has 12 SATA ports; someone with very specific, bordering on fetishistic, approach to memory and storage might be able to make a case for it.
If you need that many SATA ports though, you might want to think about SAS storage, for which the ASUS P6T Deluxe has two ports. Coupled with the fact that MSI’s Eclipse is showing up at prices at or higher than the P6T with the OC Palm device ($365), and the Eclipse is far from attractive.
Without the OC Palm, the ASUS board can be had for about $330, 20 bucks more than Gigabyte’s UD5. But the UD5 seems a hair faster. At about $360, the Extreme product from Gigabyte is a solid buy for someone planning to use liquid cooling. The non-liquid option for the Extreme looks pretty ungainly and certainly doesn’t justify the $50 dollar premium over the UD5, the $30 premium over the Asus without Palm, or the $5 dollar savings from the Asus with the Palm.