Which monarchs were most respected and loved throughout the course of European history?
That's awfully hard to answer since there was nothing in the way of polling or anything like that.
The one monarch that stands out in this regard to me is Elizabeth I of England. History tells us that she was very well loved by her people. This may be in part because she helped keep England relatively powerful and also because she restored Protestantism after the country had been Catholic.
A monarch who was widely respected, if not necessarily loved by his people, was Louis XIV of France. This was a monarch who really brought the idea of absolute monarchy to prominence in Europe. He was respected for his power and for the glittering court life that he built up around him.