Motherbords with a wide SLI gap and new system help?

Hello,
Im looking to buld up a new system.

I want to run 2x580gtx's but....
Im concerned about the distance between the SLI slots i want as much room as posible, preferably Gigabyte in brand but im willing to try new things  . And i have never run duel cards :|

Im going to run a 2600k and its going to be overclocked and cooled respectively.

Its built for gaming basically Crysis, BC2 and BF3 when its out.

Im willing to pay around the 300 dollar mark or more (Australian moneys that is for the MB)

Also is 1200 watt PSU overkill?

gonna run win7 64x

Any advise or help would be much appreciated cheers dude's / dudets
If u want more info just let me know  )


Im currently running(if u care) a
E6600 @ 3.6ghz
4 gig ram
1x GTX 275
Gigabyte EP45-UDP3
Win 7 64x
several hdd's

is it worth the upgrade yet???