Soros definitely was once a huge market mover, back when he was still active in the markets.
Current day market movers include Bill Gross of PIMCO when it comes to interest rates and the fixed income markets and Kramer for the stock market. I can’t think of a specific trader/fund manager for forex that has a lot of punch right now.
These guys, though, pale in comparisson to government and regulatory figures like the Fed Chief, Treasury Secretary, head of the ECB and the BOE, plus the BOJ. Really any person with responsibility for monetary policy and/or interest rate decisions for one of the major industrialized economies. And of course heads of state.