Which OS is better for a 130-client Server?

Which OS is better for a 130-client Server?
What I mean is that I’m to write a proposal to get on with server erection and its architecture design but I still am in dilemma whether linux base server goes with this 130-client server or the windows server 2008? You know what, I am searching the upsides and downside for both linux and windows! well on the budget, consider there wouldn’t be any restriction and all the lettuce will be provided as need ! but the heart of the job to me is the way of simply putting which OS can go with my hardwares( which is CPU:INTEL XEON AND THE MOTHERBOARD: SUPER MICRO) BETTER?