Two of Chaim Potoks novels are "My Name is Asher Lev" and its sequel, "The Gift of Asher Lev". I'm surprised this name isn't more popular, given that it has a great meaning, is practical and easy to spell, and is one of the 12 tribes. (Not that being one of the 12 tribes in itself guarantees popularity.) And I almost forgot to mention, we have a son named Asher who was born in 2002.
As many people have mentioned, this is the name of a character from 'The Giver'. To the person wanting to name a son Gabriel Asher, I wanted to point out that Gabriel is also a character from 'The Giver' (he's the new child that Jonas' dad has to watch over, and Jonas eventually rescues from release). Anyway, this is a pretty nice name. It sounds like it could be used for a girl or a boy.