Giant Robo has an unusual intro and not much to speak of in way of an ending.
But everytime I hear that unique opening, I just have to see the series all
over again. This question is semi-ironic, because we are currently converting
GR for our video iPod (again!) so I get to hear the intro over and over.
There was a firmware upgrade for the iPod which allows for near DVD quality video.
Especially hooking it up to the TV, you can't tell the difference!
Some other series with great OP/END are Outlaw Star, Midori Days, G Gundam,
Brigadoon, Escaflowne, Heat Guy J, FLCL, Berserk and the newer Cutey Honey
anime series and live-action movie.