I will say Royce Gracie but I will have to say Ken Shamrock as well. However I really didnt start to like him untill his Gracie Super Fight. He did what no one else had done before in the UFC....prove that Gracie could be beat (although he did not win...draw) But he still showed that if you fight without making a mistake, the guard is only a defensive possition. But stopping the man that everyone thought had the greatest offence.
Others would be Hughes and Franklin, but they are more like modern day motivators. Gracie and Shamrock got me started.
Another great motivator is Tito...I want BEAT HIM DOWN SOOOO BAD... oh sorry about that >.< But yeah I hope to be in the UFC before he leaves.