Working with a paper-based list most of the time is also important for me: My computer usage has been a lax one most of the time: when I stare on a screen a part of my brain screams "emails!", "flash games" and "lets have fun". This is not a problem of OF, it is me: The medium has become the message.
I have an iPod touch so that I don't have to go back to my computer and "accidentally" check my e-mail.
OmniFocus is probably the most accessed program on my iPod touch. I don't have to be anywhere near my computer to check off an item or to scan my next action lists. Thus, it prevents me from hitting YouTube.
I never thought I would like OmniFocus for the iPhone that much! But it's actually pretty cool to have my next actions at my fingertip.
The best thing to do is to set your default home page to a blank page instead of your favorite web page. Or better yet, just quit the web browser, e-mail, and instant messenger program to avoid distraction....