Firefox Developer Edition

Mozilla have recognised that web developers have a completely different way of working and interacting with their browser. Not sure what their roadmap is but I think keeping all the Developer Tools out of the mainstream Firefox and in the Developer Edition would be a good move. If you fancy the Developer Edition then head over to Firefox Developer Edition — Mozilla for a closer look.

However it is worth noting that the reporting of telemetry data is turned on by default in the Developer Edition, unlike normal Firefox releases, see Firefox Browser Privacy Notice — Mozilla for details on this. However you can rest assured the data is sent via SSL, adheres to Mozilla's policies and can be turned off.