I really don't want personalised searches. I want the same results if I search from home, where I'm sometimes logged into my google account (via gmail); if I search from work, where I'm sometimes logged into my google account; or whether I search from a friend's house, where I'm never logged in.
It's frustrating when you know what you were looking at was one of the top few results - except that now it's not.
Of course, google's answer to this would be to be logged in all the time. I'd prefer (a) to delink my google login status from my gmail login status, and (b) be able to turn off personalised searches and tracking and all that. Option a is actually preferable, because then google would stop auto-signing me into google groups based on my gmail address, when I'd really rather not use that one for posts!