I think it depends on the job market you're in. In the US and Europe an open-source profile is expected, but over here in Hong Kong its fairly uncommon. The good ones have either flown away to the US, or already been snatched up.

But, as Alex says, once we've sifted through CVs to find the best and invited them to interview, the paper doesn't matter anymore. Human interaction, pair programming, whatever, it's all more important than what's written on a piece of paper.