'Which action, of those available to me, would be best?' -- or, in other words, what ought I to do? -- may be considered the basic question of practical moral deliberation. There are of course other questions we may ask -- e.g. 'what sequence of actions, across my remaining lifetime, would be best?' -- but it's important to note that these are different questions.
Practical reasoning concludes in action (or, to put it more neutrally, let's say implementation) . We can reason about how to act, and then do so. But while we can think about what the best sequence of acts would be, we can't implement this as the conclusion of our reasoning -- at most, we can implement but a part of it. The reasoning instead concludes in mere belief, and so is really theoretical reasoning, albeit about a topic of moral interest.
Morality is supposed to be action-guiding, not action-sequence-guiding. There's a reason for this: we can only implement actions, not whole sequences thereof.
An individual action is a true, but trivial answer. The fact that it's true explains why 'what should I do?' is the basic question of practical moral deliberation, and why the best-sequence question isn't really 'practical' at all. On the other hand, the fact that it's trivial suggests that, philosophically, we would do better to refocus on the question, 'what can I do?'
For the source of this entry, go to Philosophy, et cetera.
What we commonly do is make moral judgments about individual acts, in the context of a sequence, or against the background of having performed other acts (and omissions). I think that this is where much of our society breaks down today, there are many that compartmentalize their morality from their actions, not recognizing that their morality should be guiding their actions.