This is helpful.

I'm in linguistics--a field that has characteristics of the humanities and the social sciences. My own research is varied and includes experimental work, more ethnographic, in-the-field observing and taking notes as well as reading texts of various sorts and analyzing them. And of course the standard reading and writing. I'm recently tenured and just coming off a year's sabbatical, so my committee load both within the department and in the institution has suddenly exploded exponentially.

The groupings I use now are:

home
errands
Internet
correspondance
On campus
Brain
No-brain
Waiting

I also played with using specific research project, courses, etc as "contexts", but I tended to avoid those that weren't immediately pressing (preparing for courses and advising independent projects are ALWAYS pressing). I tried three levels of relative "brain" for a while, but I found it really didn't help much, which led me to two.

All the contexts work pretty well except for Brain/No-Brain and I'll have to fiddle around with it--maybe just call it the 20% group and leave it at that. Or I may define it in terms of whether it needs more than 15 minutes to do--as that's often the real deciding factor about what I do or don't. It's true that the brain/no brain categories are of a different sort than the others. Work for me has no specific physical location--I work anywhere I have a computer pretty much.

I've just started adding dedicated research time to my calendar and that's helpful (though I'm using it now to type this--I should probably also schedule "play" time)

I also have MailTags which filters e-mail messages into folders: Answer, Reference, Requires action (like writing a letter), Requires reading an attachment (like a student paper). That works great and has made e-mail immensely more managable.