[Iaks]

I may be outside of the normal use case here, and absolutely I am giving my opinion so judge it as one voice in 255 million (or whatever gmail's user count is now), but this isn't ever faster for me. I always have a gmail tab open.

As to remembering the source of a piece information, I made no claim to be perfect at this. What I will claim is that for the 95% of the time that I DO know the source of a piece of information I will be annoyed by results that are not from my intended search space.

Obviously Google has a pretty good track record at returning relevant results, but I can still hope for an off/on switch.

[Matt_Cutts]

At the event, they demonstrated that the same one-click toggle to disable personalized results will also disable the results from Gmail. It's not in our enlightened self-interest to push information that's unhelpful or jarring, because then you're less likely to search on Google in the future.

[rryan]

"I always have a gmail tab open."

GMail search is painfully slow (for me average seems to be about 5+ seconds) and is not that powerful (i.e. can't match substrings, etc.). I'm personally looking forward to using Google search ranking on my email. I can see using this instead of GMail search to save time.