Hugo, the Latin form of Hugh, has more heft and energy than the original-- and of course we love names that end (or begin, for that matter) with an o. This one is especially appealing because it's backed up by lots of solid history and European style. Hugo has been sitting comfortably in the 300-500 range, but this well may change due to the charming 2011 Martin Scorsese 3D movie, based on the novel The Invention of Hugo Cabret and starring Asa Butterfield.
In the seventh Harry Potter novel, Ron and Hermione have a son named Hugo; real life contemporary Hugos include Hugo Chavez, the current President of Venezuela, and the fashion world's Hugo Boss. In the past there was the distinguished Supreme Court Justice Hugo Black.
Hugo is currently enjoying mass popularity in several European countries--it's a Top 10 name in Spain, France and Sweden, and has long been stylish in the UK.
Trivia tidbit: The annual awards for sci-fi writing are called the Hugos, honoring early genre writer Hugo Gernsback.