See, I'm not as crazy as people think. :P
The '09 Mac Pro is a great system. I have found the Nehalem units to be totally stable and problem free for the most part. Certainly more reliable than the '08 model I owned three '08 Mac Pro systems and two of them died and were subsequently replaced under AppleCare with newer models. I'm usually not a fan of the whole extended warranty thing, but have found it invaluable on the Macbook Pro and Mac Pro systems.
And yes, the 8-core 2.93GHz holds its own just fine against the current 2010 tower. The only real advantage the 2010 Westmere systems have is the extra memory speed (1333MHz vs 1066MHz), otherwise it's the same logic board and everything. Yeah, there are the extra CPU cores on the 6-core / 12-core models, but they come at a price. You can install Nehalem CPUs into an '09 tower if you want to upgrade, but there's a flag in the system ROM somewhere that you can't change, which identifies the system for what it's intended to be - a 4,1 Mac Pro. Either way, the CPUs work just fine and you gain the extra memory bandwidth as the memory controller is on the CPU and both systems use the same EFI. Upgrading the CPUs just causes the system to mis-report (says Unknown Intel). Admittedly I don't know if there are other issues with it as I've only dabbled a bit, but it's still literally the same logic board. If there are any issues or limitations, they're strictly ROM and/or EFI based.
@ L. Langer -- OpenCL is where it's all headed. CUDA is great and has the technical edge in many ways, but the gap is closing. OpenCL is to GPU computing what OpenGL is to 3D graphics -- an open standard. With OpenCL, no one is locked into one manufacturer and that has been a huge sticking point with workstations here, both Mac and PC. The new ATI 7900 series GPUs have a lot to offer and look great on paper. But they're not a serious purchase consideration for a lot of us because several apps are reliant on nVidia's CUDA. This is finally changing, which we all knew it would, but it's one of those things that didn't have to be this way...
On the flip-side of the coin, nVidia originally offered up CUDA to be the open standard. The rest of the industry pretty much said "thanks, but no thanks" and then fell behind in their wait for OpenCL to come to fruition.
@ Subhadip -- Pretty much agree with everything there you said about Intel's fabs and supplies, emotional attachment, etc.. I think Intel's supply issues right now are mostly getting C600 chipsets out to board manufacturers. It's the motherboards that are in short supply... I can buy E5-2600 CPUs everywhere -- they must have stockpiled them ahead of release since they were not the holdup, but rather the C600 series chips. In addition to that, third-parties are having issues getting the PC3-12800 RDIMMs to market, especially the CAS-10 and faster ones at 8GB and larger sizes. I finally just received some from Micron to put on one of my SuperMicro boards. But I ordered 256GB worth of 8GB modules. They sent me 8 DIMMs so far, so I guess I'll start with 64GB.
The emotional attachment to one platform is understandable. People have to be comfortable with their tools in order to be productive. Personally, I'm very comfortable with both Windows and OSX, so regularly work with both and if Apple pulls up short on a new Pro offering, well, then I guess I won't be buying a whole lot more in terms of Apple systems. I do prefer OSX over Windows for many reasons, primarily my fondness of days spent in SGI Irix and other unix derivative platforms. Coming from the world of SGI, Sun and DEC/Alpha, the walled-garden of Apple doesn't bother me so much. But Windows is still where it's at for the most power and freedom. You still have to build some walls though, to continue with the metaphor... Windows still requires a lot more attention to threat and pest control, virus, worms, malware and spyware.
And I totally agree that waiting around for the next best thing is rarely a good idea. I've always approached system purchases with the same perspective. If I don't need it right now, I don't buy it. When I do need it, I buy the best I can budget for. I try not to make any purchase of rapidly-evolving equipment (like a PC) unless I know I can earn a complete ROI within 12 months. I might stretch that to 18 in extreme circumstances. So on that note, I'm not so sure I sympathize with those who feel they've made a massive investment in one specific platform. All things come to an end at some point and we can't always predict or attempt to know when that might be. Between the HP Z820 inbound and the two other E5 workstations I'm building, I think that does it for me until something better comes along. I'm satisfying a need for a couple new workstations and a client is floating the bill for my Z820 (other peoples' money, yay!!). Beyond that, the whole SB-E5 platform is just not that special.
The PC world may be free and open, but it's also an example of overzealous backward-compatibility and legacy support taken to fanatical levels. As big and powerful as these new Xeon workstations are, they're still starved for PCIe expansion space. Even if they have the slots, it's near impossible to use them all. And then HP and Dell both go and put a legacy 32bit 33MHz PCI slot in there. At least they both positioned it so a dual-width GPU can cover it up. Sure, I understand. Gotta keep the corporate purchase lists satisfied and the oddball business that just can't buy a new system unless they can install some 15 year old interface card for some abstract device... But really, come on. In the top of the line, flagship workstation, is this really necessary?