since i'm avoiding clogging my noggin with info I don't currently want
I found this for you...froma tomshardware forum post:
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A good P35 board like the DS3L will serve you well until Intel releases their next line of processors (Nehalem) early next year which will require a new socket.
PCIe 2.0 shouldn't be necessary before you will need a new motherboard and processor, so don't worry about that.
X48 is not DDR3 only. In fact, X48 is little more than a glorified X38 rated for higher speeds and better timings.
One last thing, you don't need anything more than DDR2-800, even if you're overclocking. I can show you the math if you want
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The guy seems informed, others here can refute or back him up

forum posting was dated 02/11/08
this was talking about p35/x38/x48 comparisons
and the tomshardware relevant review for you
Crossfire up to 20 Percent Faster : Crossfire meets PCI Express 2.0 – More Lanes, More Frames?
no brand input from me though