AFAIK, there's not a single tool for all browsers.
However, storing passwords in a browser seems a bad choice anyway if you have a look at how easily they can be retrieved.
I suggest using a password safe such as KeePass and the auto-type feature instead of storing passwords in the browser.
Firefox
I use Nirsoft Password Fox. Note that it comes in 32 Bit and 64 Bit and you have to use the version that matches your Firefox.
✓ Easily recover passwords: run the tool, all your passwords are displayed.
✓ Save passwords as: Text, HTML, CSV, XML (press Ctrl+A to select all)
✓ Recover lost passwords of any website: of Firefox
✓ Free or paid: free (closed source)
Internet Explorer
I use Nirsoft IE PassView. It's free. Same author as before.
✓ Easily recover passwords: run the tool, all your passwords are displayed.
✓ Save passwords as: Text, HTML, CSV, XML (press Ctrl+A to select all)
✓ Recover lost passwords of any website: of Internet Explorer
✓ Free or paid: free (closed source)
Chrome
The same author has also written ChromePass, but I have no experience with it.