One nice thing about traveling to New Zealand was that I spent several days disconnected from e-mail. I went a whole 80+hours without checking my mail on both ends of the trip. It was nice. (I could have checked mail, but in New Zealand it seems like all the hotels make you pay for Internet access. I didn't feel like paying. Of course, I had e-mail available at the workshop.)
The experience has suggested to me that I ought to try moving to limit my e-mail during the day. It seems more productive to set aside time to specifically deal with e-mail; maybe first thing in the morning and last thing before leaving the office. I'm not sure how this would work with other people, though; many people treat e-mail like it's a phone call, an immediate connection (including my wife), when of course it's not. I often see "emergencies" pop up in my e-mail box; while I was gone, I was asked to call somewhere for my opinion of a job candidate, and an NSF director wanted me to expand on my research nugget (as usual, by yesterday preferred, by tomorrow would be OK). These people didn't need to get in contact with me that second, but there seemed to be the clear expectation that I'd see their message and move on it within a small number of hours. Is that a realistic expectation?
Of course, these weren't real emergencies, and making a practice of leaving e-mail aside and blocking my e-mail time better would probably increase my efficiency, and possibly my happiness, since I would feel less that I was constantly being interrupted.