I just read an interesting eye-tracking study: User behavior in SERPs. Eye tracking study July 2010
[dynamical.biz]. This article was translated from the original Spanish version, so it is information that many English speakers may not have seen.
The big surprise for me was not that different intentions meant different eye tracking behavior - although there is some meat in there too. The big surprise was that the snippet attracted a higher number of fixations than the title element did - and this was for EVERY intention category.
The study looked at these four query types: informational, navigational, transactional and multimedia. One big takeaway for me - there's a reason Google Webmaster Tools gives us quality reports on our meta descriptions, and it's a stronger data-driven reason that I would have guessed!