In the URL entry box, type "www.goo" and a dropdown list will appear with
"www.google.com" and any other URLs that start with "www.goo".  The user
can hit the down arrow key and up arrow key to navigate up and down in this
list.

I request that the Tab key should work the same as down arrow, and
Shift+Tab should work the same as up arrow.  This should not cause any UI
confusion, because the Tab key will go back to its usual behavior if the
user hits the Esc key to get rid of the drop down list.  Also, other web
browsers such as Mozilla, Galeon, and Mozilla Firebird support this use of
the Tab key.