Two weeks ago, the popular Mac-only desktop email client Sparrow released the iPhone app, and it is really, really good. It does, however, have one catch: It doesn't (yet) support push notifications. To that I say: Who cares?
You may have a job where email is the primary form of communication and you need to respond to every email the instant it arrives. If that's your job, I'm sorry. This post may not be for you.
For most of us, instant email back-and-forth is not nearly as important as we make it out to be. Yes, email is where a lot of our most important communication happens. But email isn't something that requires you to drop everything the moment something new pops into your inbox. That you think so is an indication that email is probably screwing up a lot of your day.
Despite having heard countless times that multitasking is a myth, you may consider yourself a master multitasker. OK, fine. But believe me when I tell you: the vibrating pulse in your pocket indicating the arrival of a new email; the unpredictable "ding" from your desktop's email notification; these things are killing your focus and destroying your ability to work to your capacity.
Stop worrying whether your pocket buzzes the instant a new email arrives. You shouldn't let it do this anyway. Check your email in batches. Schedule in your email time. Do it as often as your job requires. Once an hour is probably more than enough for most of us. Better yet, make it twice a day if possible. Respond thoughtfully, when your time and energy is focused specifically on checking and answering email.
If that sort of schedule is a problem, you may want to consider a new hierarchy for your communication. At Lifehacker, email between staff is relegated primarily to non-urgent communication. By non-urgent, I mean communication that everyone is expected to read (and if necessary, respond to) at some point during the day. For urgent group matters, we have a group chat room. For urgent individual matters, we have IM, or even SMS.
This hierarchy of communication is important. Yes, it requires people at your work to adopt and use the hierarchy. But it's worth it.
As for push email? Turn it off. Your sanity (and battery) will thank you.