For myself, I prefer that puzzles echo the flavor of the campaign. The best one I was ever on the recieving end of was in a long running D&D campaign. We found a round table, with a milky, translucent top, and edged with gems. A ring, too big to wear, lay in the center. Fortunately, one of the players had seen the 1960 version of "The Time Machine", and knew to spin the ring on the table. It gave us a riddle:
"The beginning of eternity,
the end of space and time,
the beginning of every ending,
the end of every rhyme.
What am I?"
We tried many solutions, all way too literal. Each failure trapped the answerer in a gem on the table's edge. That was over 25 years ago, and I still get goosebumps.