After extensive planning and development, multi-process Firefox (aka Electrolysis or e10s) is here with Firefox 48. The jist of it is this: web content and browser interface processes are now separate, so if a page is hogging resources, your tabs, buttons, and menus will no longer lock up.
E10s is rolling out slowly; to check if it's enabled for you, type about:support into the address bar and check the line that says 'Multiprocess Windows.' If it says '1/1 (Enabled by default', you're good to go.
The awesome bar also gets significantly more useful with the 48 release: many more suggestions, each showing more information now show up when you begin to type in the bar.