So far from my chronological viewing of the series, this is the most moving episode yet for me. For anyone who has lost a parent, they can relate.
But this episode deals with death on different levels. It deals with the concept of the temptation of living in the past and ignoring the reality of loss, and mentions the strength of humanity in overcoming the acceptance of our mortality.
There is a great conversation between Data and Riker, where Data questions why we do not equally mourn the loss of those we are close to and those we are not. Riker makes a compelling comment while explaining this to an android, and it ends with Riker saying that if we mourned all loss of life equally, humans would have a much less bloodier past.
This episode brought laughs and tears. The ending with Worf and the boy was great, it made Worf out to have a decent and likable character inside of him.