1- What 890 mobo?
2- Today u maybe won't see a big difference with a quad-core or a six-core, since only few games can use the 4 cores.
3- What other components u want install with the rig?
the 955 i have now came with a free MSI 890GXM, the 1055t they offered comes with a free Gigabyte 890GPA Mobo
i have 1tb SATA II HD, 630watt psu, DVDrw and im gona get a 5770 and 4gb DDR3 1333
my last system had a Pentium 4 478 4ghz, Intel 865PEPro 2 mobo, 7800GS AGP 256mb DDR3 256bit, 3gb DDR400(which will all be sold), i was always too cheap to upgrade but most games nowadays wont even play on medium settings with my old system so this is a considerable major upgrade for me
as long as the 1055t works the same as a 955 im fine paying the extra $40