boards
sli=tforce 590, check it out, my buddy just got 2(one for him one for his boss) and they overclock GREAT and the package is kickass spely compared to other 590 boards.
crossfire, i would get the ECS board for now, in my exp and that of people i know it seems to be the best bang for the buck, overclock VERY well and has the least issues of any board using the 3200 chipset for am2(not alot at the moment), i have seen it push 465fsb without a swet(beta ecs bios they sent us by request!!!!)
and honestly i would just get a 3800+ x2 and overclock it to 5000+(2.6) or higher(have yet to see one that on a decent board wont do 2.8-3.x gz)
then wait for mid year when the k8l comes out, for gaming you wont se a diffrance between the e6800 and the 3800+@2.6 even with a 8800 card.
the 6*50 chips need new boards/chipsets they use a 1333mhz fsb, also they arent due out till after k8l from what i have been reading(q4 or q4 of this year for the 6*50 chips)
if you game, worrie about video card and ram more then what cpu you get, ocz gold 533 4-4-4-12 1.8v ram will clock to 830+ at 2.2volts!!!!! (its what i have for my 2gb kit)
another SLI board option is the tforce 570(hard to come by because they sell out so fast, egg cant keep them in stock) or the asus msn-sli delux but warrning about the asus board, you need to be willing to use Ketxxx's moded drivers for the audio(after using them its better then my audigy3 by a long shot) and be willing to put up with some bios querks, i have one, its ok, i would rather have the tforce(my 550 is being rma'd), they have less bios problems and better clocking fetures.
personaly i would eather hold off till k8l comes out OR get a temp cpu to hold me over(what i desided to do) because for gaming ur not gonna see the diffrance unless you SLI a couple 8800gt* cards and run at uber high res's(1920 and up) then the diffrance is small.
honestly u got 939 i would just find a dual core cheap to hold me over till mid year when the new stuff comes out then deside what i really wanted to do, by then ram prices will be lower, more boards will be avalable for crossfire and sli , and you will have a better idea aboutt whos chip is gonna be better for you next upgrade!!!!
also by then the r600 and other ati dx10 cards should be out to, again, this would let you choose between more types of hardware then are currently avalable, in the end saving you$$$
my buddy just got an opte 175 for his 939 rig at at stock volts it at 3.1gz, at +.125v he got it to 3.3 using his freezer64 pro(moded with a panaflow fan because he broke the orignal one when he droped the cooler the day he got it
)
cheap and effective and saves you from excess expenditures for a while
(save that extra $ up and get whatever is top of the bang for the buck heap q2 or q3 of this year!!!!!