I am a huge fan of the auto-dimming rear view mirror I installed. $11 from a junkyard, I highly recommend it.
What about heated side mirrors so they defrost themselves? I think those have reached the junkyards as well.
Another great upgrade would probably be an HID retrofit. They make really tiny projectors now that may just screw into your headlight socket, if they fit.
Bi-Xenon Morimoto Mini H1 install - Honda Civic Forum