Shhh... I have discovered the secret to productivity. And because I am your bloggy friend, I am going to share it with you. (Warning: you're not going to like it!)
Step 1: Drink coffee. (However much you need.)
Step 2: Plant your butt in your seat (desk, reading chair, whichever seat the task calls for).
Step 3: Start working. DO NOT check email accounts, Twitter, your blog, or any other site on the internet that is not directly related to the work at hand!
Step 4: Keep working.
Step 5: Break for lunch.
Step 6: Return to your work. Again, DO NOT do any of the forbidden activities listed in Step 3!
Step 7: In the late afternoon (around 4:00 or 5:00), you then may check your email, blog, etc.
See? I told you that you weren't going to like it. But, dude? It totally WORKS! I have been more productive in the last week of practicing this discipline than I've been in months.
Now, this of course won't work for you quite as well if your work requires that you check email or other websites regularly. But if you limit yourself to only the absolutely necessary internet activity, and develop some rules for when/how long you will deal with email at a time, it still might work for you.
It isn't nearly as much fun as twittering the day away, but it's much better for actually getting something accomplished.