I think we are nearing the stage where "Absolute ranking positions in the SERPs are dead".
For a wide variety of reasons the SERPs you see are not the SERPs I see. Personaliztion, user's last query, geolocation (as you have noticed), competition, data centre update cycles, etc, etc all contribute to making the kind of measure you are describing less and less meaningful.
Gary, you might take all the good steps you can to get your site ranked locally - including Google Business Center and Maps. It is remarkable that a site would rank BETTER outside itsn geographical area!
We have a forum for Local Search [webmasterworld.com] that might offer some help.
Yes I checked, not logged in, personalization off, not much differance there. It seems like for local results the national brand site are pushed to the top and out of state and country they are pushed down. Actually the further away they are the stronger I rank. My server is in the US and address is local and phone is local. Was just wondering how to get #1 for local also...