Originally Posted by Duekster
Google does seem to serve up what they know you have already searched for and viewed. Particularly if you 1+ your own site. You told Google this is a site you want to see.
I also notice they mix up the results on Google places often. I suspect it is helpful to clean out cookies, and temp internet files and also use different browsers and such when trying to check the results of your SEO efforts.
I think also it would be helpful to have others with different IP's to dual monitor as you say. Many times my search results are based on a city 30 miles from me because that is where the IP originates and some times it is closer to home.
The bottom line however is to look at your server web stats, and the webmaster tools both Google and Bing offers as well as how often does the phone ring.
You're correct, Duekster, and absolutely Google's 7 Pack of results (the 7 slots set aside for local results) can be as fluid as regular search. Kirk's search results (not Kirk's knowledge of how search works) are a great example of this. He sees one set of results (6 organic listings on page 1), whereas I see his Google+ at the top of the 7 Pack, and then Yelp and Facebook links in the organic results, for a total of 3 links on page 1. If I search from a "clean" session, I see the same results as if I'm signed in. If I search from San Francisco, I don't see his Yelp listing.
I do actually monitor several sites search ranks from a variety of IPs, as well as when logged in or out of Google. I don't bother much for nationally-targeted sites (the organic results tend to be what they tend to be), but I do for regional and local. Being logged in to Google, or not, can create a sea change in the results served up. And, as you point out, same with IP. It's funny how, if I forget to make a change to something I use, I'm getting Ebay values in Euros and Google results for the United Kingdom.