Liam is fairly popular where I am, I don't really like it, but it works. It's short and unpretentious, boyish, but has a bit of an annoying sound to it IMO.
Liam Neeson,
Liam Aiken and a film called
Liam http://www.imdb.com/title/tt0255321/ come to mind.
That said,
William Arthur "
Liam" would be lovely. Or if you want
Liam on it's own:
Liam FelixLiam WalterLiam GabrielLiam ThomasLiam JosephLiam HenryLiam TheodoreLiam ScottLiam GregoryLiam DanielLiam Nathaniel Liam David
Like any?