Jobs with memory (and their effect on our well-being)

I'm interested in what you guys have to say about this topic.

A recent post on HN, "A good day's work" (http://37signals.com/svn/posts/3180-a-good-days-work), reminded me of this issue, specifically the problem of not being able to mentally disengage from work if you have a certain type of job.

Do you know of any studies as to the level of happiness of people with "jobs with memory" (long term projects) vs "jobs with no memory" (e.g. waiters, cashiers, ER doctors)?