When my manager stops freaking out when an email goes unanswered for 10 minutes (or I get a new job), then I'll stop checking my email so often.
When I last went job hunting, I would say to the interviewers:
1. I will check email 3 times a day. When I come in, around lunch, and before I leave. Is this a problem?
2. Do I need to use any kind of IM on this job?
If lots of email bother you, set your standards higher.
Edit: Reading other comments, I should add: I also point out that physically interrupting me in my cube is OK. Or calling me on my office phone. If it's urgent, come to me or call me. If not, send an email. People treat IM as "urgent" but then don't act as if it is. So I "ban" IM for myself.
Was going to say exactly that. Works for me too. I'm amazed more people don't do it.
I use a mail client set up so I'm not aware of any incoming email until I look for it....
Tell them that you check email once an hour (or whatever interval you prefer) and respond to everything in batches. You find that allows you to better focus on your core work and that you're overall more productive that way. If (s)he asks you to change your routine just say no.
Try it. It's very empowering.