If you've been unhappy with Firefox's somewhat stagnant design recently, you'll be happy to see that Mozilla is putting a heavy focus on Firefox's interface in upcoming versions. Above is one of the many mockups they're trying out for future versions of Firefox, though they note that they're just that — mockups.
They're still working with a number of ideas, and say some of the mockups they're showing off are already out of date (which is the only thing keeping us from using the words "really Chrome-like" just yet). The current nightly builds are only showing hints of these design experiments, but Mozilla says they're the best way to keep up on the new changes coming to Firefox. Hit the link to see more, or go straight to the nightly build download page to keep track of the changes yourself.