what the heck? geeks saying dont upgrade? i ditched my x2@2.6ghz a month ago for a quad and its AMAZING! i mean, it makes almost no difference.
no seriously; you read that right

95% of the time, it feels exactly the same. i guess i can tell when i'm running CAD and winrar and 18 firefox tabs and virus scanning and copying 10 gigs from one hd to the other. but just barely.
the best choice i made was ditching my 7800 gt's in sli. benchies put them slightly behind my 8800gts 320mb, but in reality its so much nicer. no more effing around with sli. textures look so much nicer and fps lows arent so bad.
stick with the x2 at least until the end of Q1 '08. let the 45nm's and the 9xxx's come out and get over the launch price like belgolas said.