Google-search – How to force Google to not mind the location during search

I can't help you with the list of any “top” rating, but!

This tool by Google gives you ability to see the amount of searches for any phrase. The default setting is so-called “broad” match data — so, if you key in recipe, you will see amount of searches for all queries that have “recipe” in them, in any form.

It won't give you a rating, but it will show you the absolute amount of monthly searches, possibly filtered by language and/or country.

For the location issue, you can try http://www.google.com/ncr

Webdeveloper toolbar extension for Firefox has a setting (there are other extensions that do this) to enable/disable cookies with a button touch, too.