For me, search on the address bar is the most important feature that I love about Chrome. IE9 has the same thing now. I am not sure why Firefox 4 did not put search on the address bar. So for a Chrome user, you will greatly miss that feature. :( Until FF integrates that, I am back to using Chrome.
(And you can use the "Customize toolbars" window to remove the search bar if you want.)
Firefox intentionally does not show suggestions in the address bar by default, because we don't want to send everything you type there to a third party.