If pricing is of no concern then its the Asus Maximus III Formula..
P.S. - Motherboards based on the same chipset perform similarly.. Thus, there is not much difference, in terms of performance, between two X58 chipset based motherboards.. The criteria for selection then comes down to the features provided, price point, aesthetics sometimes and other factors.. And it gets pretty tough to best on all of those departments.. Thus, there won't ever exist a 'best motherboard'.. It gets down to user/buyer's perspective ultimately..