Although not a royalist, I think the UK queen has done very well over her long reign. The very survival of the institute of monarchy is in no small part due to her. The money that royalty brings in must more than make up for the expense of the royal household.
Ours is a constitutional monarchy: although the queen has weekly discussions with the Prime Minister of the day, she in no way influences the day-to-day running of the nation. She does open Parliament (The State Opening of Parliament) in her "official" role as queen and head of state.
I cannot imagine us as a republic with a president. We are lacking people that we could all look up to and respect. Somehow I cannot imagine the monarchy after Elizabeth dies. It is bound to happen sooner rather than later. Will we still have a monarchy 50 years from now?