I've just ordered my second "Battle of the Planets" DVD from Amazon. I've got the first volume and the Gatchman DVD already. I love Gatchaman and it makes me appreciate how great a series it was before it was cut up and re-served to the Western audience as "Battle of the Planets" and more recently as "G-Force". This was the first true anime I remember as a kid and still my favourite. Even though it's nearly 15 years old I reckon it can still hold a candle to modern anime.
It's just a shame that this collection is only 6 DVDs at the moment. BoTP was 85 episodes and yes, you can get all 85 episodes as a box set, but not with the accompanying Gatchaman episodes - sadly.