What motherboard for crossfire 4870 and core i7 ?

[Dominic8]

I need your advice. I seek a motherboard that would:
CPU - Core i7920
Graphics Card - Two ATI Radeon 4870 (500MB) in Crossfire
RAM - 2 x 2GB 1600MHz Corsair

The goal is to play while remaining reasonable price point of view. If you see several possibilities I will take all suggestions. And if you want to share your knowledge by explaining the reasons for your suggestions then that would be great.

[Squibbit]

Which games do you play, and on what screen ... because crossfire is really the cream of the crop level graphics for the latest games, mode-all-details-to-maximum and with a screen 30"

[Dominic8]

Squibbit thank you, indeed it is important.
Base is at a time (but not necessarily at the same time) for a 42 inch 1080p TV and a dual-screen 2 x 1600x1200.
Eventually I probably add a screen 30"

Regarding the games and I would say more or less everything.
The first that come to mind: STALKER: Clear Sky, Crysis, Left 4 Dead, Fallout 3, Far Cry 2 ...

[Squibbit]

Please correct me if I am wrong:

To support a Core i7, you need a motherboard X58
To bear two HD4870, you need a motherboard with (at least) two PCI-Express.

Here are some suggestions:

Gigabyte GA-EX58-DS4
ASUS P6T Deluxe
MSI x58 platinum