jevon :
I'm also leaning towards the X38 right now. Not only for the PCI-E 2.0 but also the two 16x PCI-E slots (both 2.0 also) because both nVidia and ATI have been saying that multi-gpu systems are what they're focussing on right now. Some say thats a marketing gimick, but with the GT and 3870, CrossFireX and Tri-SLI are looking like good options! And on the ATI end, you can mix and match various cards, so you could have a CrossFireX setup with 1 3870, 1 3850, and 1 2900XT if you wanted. So thats why I'm leaning towards the X38s despite their price.
After doing more reading, I need to correct and clarify my post: The X38 does NOT support true CrossFireX. X38s provide 2x PCIe 16x lanes, then sometimes 8x or 4x. I think you can still CrossFire 3 cards if you wanted to, but they would all have to be the same model. Although I'm still a little sketchy here, as ATI's new cards are suppose to have CrossFire enabled on the hardware side.
Continuing with the X38s and their 2x PCIe 16x lanes, in January we should be seeing the Dual GPU Core 3870s (3870x2). Something to keep in mind is that you MAY be able to run two of these cards in CrossFire on the 2 PCIe 16x lanes. And again sketchy part: possibly have 1 3870 or 3850 (that you could get now) running on the slower 8x or 4x PCIe lane in a tri-Crossfire setup ---- but again, I'm not sure if this particular feautre is exclusive to AMD's 790FX chipset - it depends if the 790FX basically is just for the 4x PCIe at 16x slots, or if it also enables the CrossFiring of different GPU models (3850 with a 3870 for example). Again, I know I've read that CrossFireX is in the Hardware of the new cards... sooo yeah.. /brain explodes
NOW I'm actually looking at some Phenom options (gasp) since the AMD 790FX is the only way to eventually get 4x GPUs working in CrossFireX at full speed... although I doubt I'd get to that point before it's time to build again, I still want to know what kind of price/performance options are available when taking CrossFireX into consideration.. since GPUs are the most important component after all... my thinking is I could probably get better longevity from my system-to-be by adding 3870s or other ATI cards over time (up to four of them) to keep up with graphical demands while the Quad Phenom OCd to 3.0Ghz shouldn't be a major bottleneck for some time (though would still rather have a Q6600
Anywho....I need a drink