Just one dialog.
Lets face it, Google would prefer no user specific user control and people just typed a term into a single box and accept whatever result they thought you meant and benefits them the most.
No fuss, no bother, less confusion (and thought) and any idiot and his wallet could use it and Google could benefit.
Typing an address in and going straight there bypasses the search page and those sponsored links don't get seen.
Buy more, Buy more now. Buy more, and be happy - THX1138