Recently AidSpeak wrote a meditation on what the poor deserve (ht: Good Intentions). The point is that your view on how deserving the poor are comes down to why you think the poor are poor. Are the poor themselves at fault? AidSpeak not surprisingly believes "that the poor deserve the best we’re capable of, if for no other reason than simply by virtue of their humanity."
The post reminded me of a point from the Peter Singer book "How are we to live?". I read the book last summer, and I just picked it up from the library to skim it again. If I remember correctly, Singer considers the question of what the poor deserve, but ultimately sidesteps it. As long as your beliefs are not extreme, you probably should be paying more attention and doing more towards helping those in extreme poverty. More on this once I have finished reviewing the book.
Bryan Caplan also frequently posts on this topic. His view is that the deserving poor are those that are poor through no fault of their own. Examples are neglected children and would-be immigrants. Undeserving poor are those who have access to low-paying unpleasant jobs and do not take them. In practice, it can be hard to tell the difference. One problem with this method of separating the poor is that it is hard to imagine that anyone couldn't have exited poverty if they had been in the right place at the right time (buying the right lottery ticket, for example). Is not being in the right place at the right time someone's fault? I don't want to put words in Bryan's mouth, but my impression is that deep down what Bryan cares about is effort. The deserving poor are those who try hard to escape poverty, but are unable to.
In the end, this whole topic is Rawlsian. Suppose that everyone is doing the best for themselves, given things like how conscientious they are and how much support they received from their families. Someone like Bryan Caplan is successful because he is intelligent and working hard is relatively painless for him. Should we condemn as undeserving someone less intelligent who finds working more painful, if these personality traits are largely endowed and not chosen (Bryan also believes that parenting has very little direct effect on children's adult personalities--its all genes and environment, neither of which are chosen by children). How does Bryan reconcile these two positions?
I'm personally attracted to the veil of ignorance position. A sophisticated take on this view would acknowledge that subsidies affect incentives. If a society was to implement the (fair) "from each according to his ability, to each according to his needs" system, the only way to provide enough for everybody would be coercion. In the United States, I think it is fair to ask how close we are to the optimal veil of ignorance allocation. I suspect that much more redistribution is required. Thinking about the whole world, the distribution of wealth and health is scandalous.