I tend to love titles that have double meanings
Psycho Pass This is the name of an aspect of the system featured in the series, it is also a play on the words psychopath and as we learn it fits the series really well.
Natsume's Book for Friends Although I prefer to say it in Japanese
The meaning is what is important, again the title is literal (the name of an object the main character possesses) but also figurative (as the series can be said to be a story of the main character making friends)
Angel Beats Short and to the point and only at the end do you understand what the title means