My general feeling is that death be final throughout save for isolated "Arenas".

After all, in most story based games, you don't actually "respawn" so as go back to a checkpoint which is further back in time.  Going back in time regularly could get quite annoying.

Respawning is usually a part of multiplayer arena styled game.  I feel such areas should be obviously delineated and couldprove interesting as a tactical choice like leading a dangerous monster into a Pac-Man maze where your superior mobility would be of benefit.