I've wracked my brain for 30 seconds (because it gets sore if I wrack for too long) and can't think of any leading male character in a novel I've read recently who sports a beard.
Maybe historical romances are the exception to the rule - where the hero maintains a neatly trimmed moustache or beard a la Sir Frances Drake or the Three Musketeers?
Facial hair can be problematic for several reasons:
1. By association: the homeless man who waves a polystyrene cup at me on my way to work has a beard
2. It is there to cover up an imperfection - no chin, thin lips
3. It's rough and scratchy - girls (and boys) - have you ever seriously kissed a man with a beard? Ouch
4. Food can can get stuck in it
5. It can be threatening
I know I am being 'beardist', but when did you last see a film with a bearded protaganist unless he was evil or quirky/eccentric (and those are never the heroes)?
The right beard in the right context eg: 19th century romance, could work.
But in 2009 women tend to like 'em misbehavin' and clean shaven.
PS: This photo is of Prince William in 2008. Maybe he's compensating for the thinning pate (I'm talkin' head, not liver).