In the UK, the prime minister and the politicians he elects to his cabinet do most of the decision making. In the US,  the decision making is split fairly equally between the judicial and legislative branch as well as the president. Executive authority goes to the president in the US while in the UK it goes to the monarch.

Apple Chief Executive Steve Jobs was nearly knighted by the Queen of England. However, these plans were ended because of his failure to show at a poitical conference. The proposal was in it's final stages of approval but officials put the offer down after feeling let down by his absence.