Last night was a favorite first season episode in which Lt. Natasha Yar is killed randomly and unexpectedly by an alien life form. As I recall, actor Denise Crosby wanted to get out of the job, and the writers did a great job of giving her a typically Star Trek last moment.
At the end of the episode, after the Enterprise crew has (yet again) defeated the alien enemy, they hold a funeral for Tasha Yar. This being the 24th century, she has recorded a holodeck image of herself and so instead of someone else eulogizing her, she gives a message to her friends on the bridge crew.
I found this line particularly poignant:
"Death is that state in which one only exists in the memory of others; which is why it is not an end. No goodbyes, just good memories."