Starkers you have rocked my faith in Google so much i have resorted to using yahoo as my search engine.
Hehe, so glad my purpose on Earth has finally had some positive effect... for one person at least. I was beginning to worry Google would win game, set and match... and I hate going down scoreless. So, Doronila1, you've made my day. 
I hate defending Google (working for a major competitor) but I think I have to here. Google doesn't track your every move for marketing purposes at all. In fact, Google is the only major player to not employ any type of behavioral/user tracking.
OK, let's sift through some key points here....
The GMail part is purely contextual based on what's in your inbox. If you leave GMail, nothing you get served from Google ties into it
I think the keys here are: "your inbox" and "you get served from Google, etc, etc...." Clearly, Google can identify and locate individuals for marketing or any other purpose it desires through their IP address/email box... and nobody is going to convince me that they can't... and don't.
At most Google Analytics and Google Toolbar data *MAY* feed into their new AdPlanner tool, but this tool is purely aggregate data. It doesn't reveal that you in particular went to some site,
Again, Google can, if it wants, identify and locate users via their IP address. Therefore, when their 'phone home devices collect data for their AdPlanner tool, personal usage statistics and etc could be collected by Google, and thus, Google can determine particular sites an individual may visit... just as the security agencies and kiddie porn cops can... and do.
Google's acquisition of DoubleClick changed things a little, as DoubleClick does have some means to track people (usually retargeting - you go to some website, they cookie you, and you see ads trying to entice you to return to the website). But Google itself has even just recently introduced frequency capping (where they watch how many times you saw a particular ad and stop showing it to you to rotate in new ads)
This whole paragraph contradicts the entire premise/claim that Google does not monitor individuals. If not by name, it is identifying individuals via their IP address and net activities.
In reality, most of the data google has about you, aside from being completely anonymous isn't even tied together. That they record a user going to a site for reporting purposes with Web Analytics doesn't have anything to do with what they see you do on your searches
Again, nobody is anonymous or 'just' a statistic... because an IP address is an internet fingerprint and can be/is traceable back to you.
Why do I NOT believe Google does not gather and retain data on individuals?? Because knowledge is power, and advertising power = income = money = more power.... and Google is a ravenous glutton for all of them, which is why I will never be convinced by comments/statements to the contrary posted here... or anywhere else external to Google's inner sanctum, for that matter. It not like anyone outside that circle really knows for 100% sure... and Google is highly unlikely to admit to practices that an overwhelming majority would frown upon with total disdain.
My distrust/dislike of Google, however, will not stop or frighten me from using the internet... nor will I cease or desist in saying exactly what I think of it. I mean, what they gonna do, just go ahead and shoot me???