In my Firefox install, I have the best of both worlds, assuming you know much about computers. I press the Alt key, all my pull-down menus appear. A couple clicks to do whatever I want. Which just happens to be what Windows Explorer does, as well. Consistent interface, no wasted space, and even the useless stuff is an instant away.
Sure, when you're browsing the web, more screen being used for the pages is good. But don't waste my time by forcing me to use your special interface. I'll lose far more having to learn yet another non-standard interface than I will by losing a 1 cm row of screen space.