I think there are more important things to tell children than how fabulous they are for something that, lets face it, they can't change.
Praising effort, yes, even other skills that they have, especially those they've worked hard on, even if they have a natural talent too, that has made it for easy for them.
But to praise all the time for how they look, which can not be altered much apart from by preening themselves/slapping on the makeup to hide what they really look like, seems daft to me. But then I don't set much store on looks.
I especially don't like it when people tell girls they are gorgeous/beautiful/pretty but wouldn't dream of saying similar to their brother, telling them they are clever, strong, funny etc. Sadly there are people like this!
In my opinion, all that praising looks does is make them think that looks are important and that others should be judged/valued on how they look, to the exclusion of other qualities (which I personally view as more important- e.g. personality, kindness, thoughtfulness etc.)
This is not to say that I don't think compliments are appropriate e.g. 'your hair looks lovely like that' or 'that colour really suits you' or 'those new trousers look great on you'. It is just the unqualified 'ohhhh you are soooo beautiful' that I don't see the point of.