THe Google search page you normally see is targeted to your specific needs, or at least Google tries hard to taylor it towards your ‘need’. THe IP address of your machine gives the geography where you sit and any gmail/google login gives tons of data. Who knows how many cookies and history-sniffing little apps are at work when you pless the search key.
To get the best raw data in SERPs [Search Engine Result Pages] it’s best to eliminate the bias toward your personal profile. A great tools for this is the free site at Goosh.org – Goosh is short for the ‘Google Shell’ – It’s very bare-bones and delivers text only and is limited to 4 results at a time – simply press enter to get the next 4, and the next, ….
The best SEO advice I know is to use the google search tools like a ‘normal person’ would. Ask some friends to show you how they’d search. Look at the keyword tool results to discover tems you haven thought of. Once you get the top results you should visist the sites and see wht they’re doing and start you’re R&D.
The goosh.org tool is a good place to visit on a regular basis. I try to look every 30-60 days and see what has changed. You may like to print the top 12-20 results and put them in a file to visit monthly. After a few months you should see some movement in the list from your site or others. This is the bet way to get a pure reference point and a clear picture.