This.

Startups are an acute instance of "too much to do, too little time". Good task prioritization might be the SINGLE MOST IMPORTANT skill that a startup founder needs to develop.

Not all failures are time wasters though -- some of the items in that list seem reasonable enough (techcrunch amazon affiliate links).

DHH said something like "If you're not working on your single best idea, you're doing it wrong". He was talking about startups, but I think that could be applied to your to do list as well.