Most successful traders who I personally know (not online) are also Forex traders. But cost of trading... I just cannot accept it especially if trading something else besides EURUSD, GBPUSD. I remember I hold USDRUB for 4-5 months, it took 50$ for out of 300$ profits. I guess it was 0.1 lot (an equivalent of 1000$), in futures it would cost 8$ for me, but it is also approximately 41 time more (something around 41k$ per contract), so this would turn out to be 2000$ in costs through forex broker. But of course I didn't have enough money to trade this amount in case it would go against me, so the only option was forex for me, as for most retail traders anyway. :)