Interesting article in today's New York Times: Lost In E-Mail, Tech Firm Face Self-Made Beast. The article examines efforts by many companies to understand the impact of constant interruptions on productivity.
Companies are finding tremendous results in forcing people to stop distractions for a period of time each day, devoting that time to thinking or getting real work done (such a concept!). The article cited a Basex study which placed the impact in lost productivity in the U.S. due to distractions at more than $650 billion annually!
Take the time to read the article.
Better yet, everyday, try to take at least one hour off---don't check email, don't answer the phone (landline or mobile), don't use your Blackberry, don't surf the web, don't sit in a meeting. Use the time to think, prioritize, or get some real work done. You'll be amazed at what you accomplish.