Buying new computer readvise my specs please :)

POWER SUPPLY Upgrade: 1, 000 Watts Power Supplies (Xion SuperNova AXP-10000R14HE)
CPU: Intel® Core™ i7-920 2.66 GHz 8M L3 Cache LGA1366
COOLING FAN : Asetek Liquid CPU Cooling System (Extreme Cooling Performance + Extreme Silent at 20dBA)
MOTHERBOARD: (3-Way SLI Support) Asus P6T Intel X58 Chipset SLI/CrossFireX Mainboard Triple-Channel DDR3/1600 SATA RAID w/ eSATA, GbLAN, USB2.0, IEEE1394a, &7.1Audio
MEMORY: 6GB (2GBx3) PC1333 DDR3 PC3 10666 Triple Channel Memory (Corsair Dominator
VIDEO CARD: NVIDIA GeForce GTX260 CORE 216 896MB 16X PCI Express (EVGA Powered by NVIDIA)
VIDEO CARD 2: NVIDIA GeForce GTX260 CORE 216 896MB 16X PCI Express (EVGA Powered by NVIDIA)
HARD DRIVE: Single Hard Drive (1TB (1TBx1) SATA-II 3.0Gb/s 16MB Cache 7200RPM HDD)
Data Hard Drive: Single Hard Drive (1TB (1TBx1) SATA-II 3.0Gb/s 16MB Cache 7200RPM HDD)
Optical Drive: Lite-On IHOS 104 4X Blu-Ray Player
Optical Drive 2: LG 22X DVD±R/±RW + CD-R/RW Dual Layer Drive (BLACK COLOR)

allright so theres the main stats of the computer i'd like to buy
i havn't bought a new pc in 6 years so it's about time
this is majorly for video game use
few things im not sure about is the graphics card wasn't sure if i should get 1 295gtx or sli 260's (oppion's please?)
6gb mem good enough?

feel free to edit and advise any of this i wanna make sure i make the best computer on a affordable budget! thank you

also, i was wondering about directx 11, if i have the gtx 260 or 295.. will they work on directx11? since it wasn't made for it?
(and no i don't want to make my own.. i wouldn't even know where to begin with that)