Funny, I feel the exact opposite. The FreeBSD style(9) documentation suggests tabs because they can be customized to individual developers needs and they minimize weird diffs on the version control systems.
I take language and platform into account. For HTML and JavaScript, I prefer spaces. For Java, Perl, C#, CSS, C, and C++ tabs. If there is a crazy IDE required, I often prefer spaces because many of them default to some level of spaces and I like the quick code cleanup command to work the same for the whole team.
The real issue with that question is that it's impossible to answer. Even if you get a "spaces" person, try to get them to agree on the number of spaces. A coworker loves 2 spaces which is flat out wrong to me. Too hard to read. I've met people into 3 or 4 spaces. Then you get into where to put curly braces, etc.
Whatever you choose, it should be a standard for code whether at an open source project or a company.
I can't stand everyone using their own style. It's much worse than having to use a specific one.