I work in the IT field and it's incredibly easy to be constantly distracted by emails, pages, phone calls, etc. at home. I've committed to not even turning the computers on at home so the only person that really uses them is my wife. The biggest factor I've found is just the mental and emotional detachment just checking your email causes, simply because you've got another problem that's now fighting for your attention.

I love the "take the long way home" suggestion. My wife and I have carpooled to work off and on for several years and I just need time time to switch gears before I can really enjoy or process anything else after work. Depending on the day, I like to listen to some good tunes or maybe just drive home in silence, so I can make sure that my emotions and my head have enough time to get rid of the stress and frustrations of the day.