Only one thing makes me deliver: deadline
Without deadlines, nothing gets done in my world, as I always get these ideas of how to do something better using the new shiny thing X and there is no end to it.
Deadline enforces discipline and requires me to do a good job of planning to allocate the precious time. Makes me say no to pleasant distractions that I would otherwise agree to...
Once I have something delivered (or during my consulting work), then I allow myself to go on a "sabbatical": read the books and lurk on HN and LTU. However, the sabbatical must have a scheduled end-date too, otherwise nothing will ever get done.
Deadlines must be concrete. Here are mine: my current sabbatical ends in 2 weeks (coincides with the end of my consulting engagement and loss of golden handcuffs http://news.ycombinator.com/item?id=763743). Real work starts on October 4 with a clear deliverable by October 23...