Robotech is butchered versions of Macross, and two other series that escape my mind...
Sukeban Deka was a live action series based on the manga before it became an anime.
the movies for Galaxy Express 999 are pretty cool with Captain Harlock and Queen Emeraldus as supporting cast from the pen of Leiji Matsumoto
Space Battleship Yamato was the forerunner for most of the current wave of anime mania that swept Japan since the early '70's, and this series mutated into the english adaptation of Starblazers (that removed all references to the history of the Battleship Yamato)
For those with an interest with legends and spooks should refer to series like Nippon Mukashi Banashi (Japanese folk tales) for an amusing look at many of the legends of japanese folklore
Other series include: Ge Ge Ge no Kitaro that dwells upon the supernatural world...the black and white version was apparently scarier than the watered down modern colored version out these days
For even older stuff there are shows like Sasuke, one of the first
Ninja-style manga adapted into anime; Umeboshi Denka, a japanese version of warped I dream of Jeannie and precursor to Urusei Yatsura; Kaibutsu-kun is a Japanese parody of the Addams Family...
Then there are the shows about more ordinary family settings, like Sazae-san, Osamatsu-kun, Bakabon, etc...
but it is unlikely that you'll find any of the really early stuff until they re-release the stuff...