Safari is brilliant here. If you enter something in Safari's location bar, it will suggest Wikipedia and other search suggestions right away [1]. I use this feature all the time. But FF, out of the box, will only show suggestions from one source. Here [2] is what FF suggests; all the hits are from Google, and it doesn't try to be clever about showing what I might mean to search for. Notice how it offers to search Wikipedia, with this tiny, obscure icon at the bottom of the suggestions, which I find to be a completely useless feature (I have keywords for that). The top hit tends to be what Google puts in a special box in its search results.
Here is another nice thing Safari does [3] which I make use of all the time. I've not visited walmart.com, so that "Top Hit" is just because it's a popular site. I can't make FF do anything like that.
[1] http://i.imgur.com/83FfnPn.png