Windows: RoboForm, one of our readers' favorite password managers, is only officially available as an add-on for Firefox and Internet Explorer. Unless you grab a custom Chromium build with a RoboForm adaptor built in, crafted by the RoboForm team itself.
The build is Windows-only at this point, and requires a separate installation of the RoboForm software. But for those eager to use the well-regarded password storage and auto-filling features of RoboForm, or who aren't using Xmarks for Chrome, it's a pretty handy solution.
RoboForm and the adaptable Chromium build are free downloads for Windows systems only.