This is a question that defines the person asking it. It is very different from, "here's what you might need..."
If you ask people for the next task on the list, if you allow them to define the thing they are buying from you, you have abdicated responsibility. Your work product becomes dependent on the insight and guts of the person giving you an assignment. This is especially dangerous for consultants and freelancers, because the answer might be, "nothing." Or it might be a paying gig that's profitable in the short run but a career deadener over time.
Far better to reach a level of confidence and skill that you can describe solutions rather than ask for tasks.
The title and excerpt above are from Seth Godin's Blog. His post had a significant effect on how I viewed my internship/how I will view any job from this point on. The day after I read his post I went to my internship and tried out his advice. Instead of asking what was needed of me, I offered suggestions on things that I could do or things that I wanted to do. It opened up a huge set of opportunities. If there is something you want, ask for it!