Ask HN: What do you use to track non-dev tasks/stories?

We're big fans + users of Pivotal Tracker for managing development related tasks (stories).

We're now considering what we should use for non-tech tasks - especially for non-developers in our small startup (CEO, product development, etc).

We want to track current tasks and have an icebox to put future tasks an ideas.

We have Basecamp but use that more for collaboration rather than task tracking - the interface doesn't seem set up to do similar to Pivotal Track - which works really well for us.

What are other startups using? Thanks!