Analingus do you even know what a constitutional monarchy is? It's where the monarch is a symbolical head of state, but in practice has no power at all. I don't know about the UK, but here in Sweden, royalty isn't even allowed to vote (or align themselves politically) - which ironically makes them the least powerful citizens.
I like constitutional monarchy, provided it means anything. Countries like Great Britain, Spain, Japan and Sweden have been kingdoms for a very long time. Monarchy is an old symbol of our nations, just like Americans hail their flag.
Sweden for example has been a kingdom for nearly 1000 years, and that's the reason why we have pictures of monarchs on our coins, coat of arms and use crowns as symbols for our nation. All of that is part of that the national heritage and it has a major historical and cultural value.
However, I've no problem understanding why some countries choose to not be monarchies. The Italy and Germany (the German Empire was just a poor attempt) of today for example are young nations, and have no real reason to adapt monarchy.
In France monarchy became a symbol of injustice and during the 18th century it became evident how the nobility and royalty had been sucking the life out of the country. As such, becoming a republic was a symbol of a new era. A lot of the people who migrated to the United States thought the same, they were tired of how European monarchs/noblemen despite being so incompetent was given so much power and so republic became a fresh wind blowing.
Today, monarchy is just a tradition here in Sweden, similar to celebrating christmas. The vast majority of us don't believe in either god or the idea that monarchs are chosen by him.
I might also add that unlike the US, both the UK and Sweden are parliamentary states and as such a president would be given no power here (sort of like it is in Germany.) In other words, a republic for us would just mean changing uniform for suit - king for president.