Here is a quick tip for Firefox: Enter Ctrl-L company Ctrl-Return. [Use Command-L and Command-Return on Mac.]
Bam! Firefox completes it as http://www.company.com and goes there.
Here is how it works. You use Control-L to automatically place the cursor in the URL address field and highlight all the text. Then type just the company name for a website (say "Amazon") and do a Control-Return.
Firefox completes it as http://www.amazon.com and goes there. This doesn't work for "non dot com" domains like .edu, .gov, .org etc. So I still have to fully type http://mobilemind.net for instance or start typing m-o-b-i-l... and use autocompleting when it finds a match.
This combination works great because the Open Location shortcut (Control-L or Command-L) does the effort-saving act of getting the cursor in the address bar ready for a new address, and the URL-entry + completion shortcut (Control-Return or Command-Return) skips the "Google-search + 'I feel lucky'" default behavior of entering just a word in the address bar. This combo also bypasses issues with proxy servers or use of the OpenDNS service, which might otherwise bring up some sort of results page to disambiguate your entry.
I now use this all the time. It saves fishing for the mouse to go to the address bar, and it is s a wonderfully handy speed combo when you're behind a proxy server on the corporate intranet or at a hotel hotspot. No mouse fishing and you avoid that disambiguation/search results page.