The thing is there are people like me who prefer a separate search bar. I don't want google search results showing up when I'm just trying to look through my history or bookmarks.
It also is a privacy issue -- if the URL bar tries to autocomplete search results, then it necessarily sends every URL you type to google/etc.
What I miss, however, is a way to configure search engines and keyboard search without re-enabling the search box. I wish it was somewhere in settings or an about: page.
Basically, when you type something in the address bar it would show your history and add "Search for ..." as the last option. So, even if you had large history, it was enough to press the UP arrow and switch from address to searching.
AFAIK, this is still the way it works on SeaMonkey.
Also Firefox's address bar is much better at searching your history, saving you from doing Google searches. For example you can type the words in the titles of articles you've read and Firefox's AwesomeBar does a good job at suggesting past entries.
This is awesome when you no longer remember the domain or url, but you remember a word or two. In such instances searching on Google doesn't help either.
This feature to me has been an epiphany actually. Google has no interest in developing something like the AwesomeBar, because they'd rather see you doing searches on Google instead.
As far as I can tell, chrome's address-bar behavior is trying to do something like the FF "awesome bar", i.e., combine searches of past urls and titles of pages you've visited, plus google search results, etc., into a single DWIM-like result.
Chrome's results aren't as good as FF's (I typically have to type more to get what what I'm looking for, and the ordering is often not ideal), but it does appear to have similar goals. Chrome used to be much worse at this, but seems to have improved somewhat over time.
As to why exactly FF's results are better, my guess is that it weights the results differently, emphasizing pages you've visited often even if the match is in the middle somewhere, whereas chrome seems to give prefix matches more weight....
[I normally use FF, but use chrome occasionally too...]
Edit: Ah, I suppose the auto-complete is different.
you need Foobar [1].
Did you RTFA?
"Firefox separates the address and search bars. Coming from Chrome, that sounds insane. Use Omnibar to combine the two."
Switched back to FF on my desktop a couple months ago when I got my keon and I love it. The only thing that's hard to get used to again is a search bar separate from an address bar. Chrome really had that figured out. A unified bar in FF would make it the perfect browser.