Well you know where I stand on this one

I was always attracted to space opera even more than cool robot designs themselves, so Robotech and Voltron I (vehicle) for me. Also, don't forget earlier shows like Tranzor Z, Gundam, Patlabor, Shogun Warriors, Micronauts, Sentai/Power Rangers, and does Ultraman count? Never watched the show.

Well, I'm a bit older than that, though I did enjoy Robotech, for its more mature storytelling. For my childhood, it was less about robots/mecha, with one exception: Battle of the Planets. This was the American redubbing of the Japanese Kagaku Ninjatai Gatchaman (Science Ninja Team Gatchaman), about a team of teenage heroes who battle an evil organization. In the original, the villains are a criminal/terrorist group, manipulated by an alien entity, through a mutant, who is a hybrid formed of male and female twins (and can swap genders), named Berg Katse. The evil group, Galactor, uses monstrous battle mecha to launch their attacks. These took the form of giant insects, turtles, airplanes, mummies, squids, warships and other things. The heroes battle them with their advanced multi-environment aircraft, the God Phoenix, their individual vehicles and weapons, while wearing coordinated costumes. The show had a major impact in Japan, spawning the sentai and super-sentai shows which became the Power Rangers, in the US.

The American Battle of the Planets was adapted after the release of Star Wars and took cues from it to tweak the series. They removed the heaviest violence from the series, due to censorship and inserted inferior footage of the Phoenix in space, to suggest that the battles took place on other planets, where it had been almost entirely on Earth, in the Japanese series. To cover edits, they inserted a robot, 7-Zark-7, to provide narration to link scenes and cover up some of the destruction, by claiming that planes and ships were robot-piloted, when they exploded. Each episode featured the G-Force team battling some battle-mecha, now from the evil planet Spectra, rather than from the criminal Galactor. The hybrid nature of Berg Katse, now called Zoltar, was hidden by referring to his female form as Zoltar's sister, or as another character entirely (you never saw a transformation, though the Japanese series makes it clear they are the same person and reveals the truth in a late-run episode).



In the wake of its success, some other Japanese cartoons were imported and redubbed, like Mazinger Z, which became Tranzor Z, and Go Nagai's mecha cartoons (based on his manga) which became Force Five. These were the cartoons and manga that inspired the Shogun Warrior toy line, which led to the Marvel comic.



Also coming in there was Star Blazers, an adaptation of Space Battleship Yamato. The premise is that an alien attack has irradiated the Earth, poisoning the planet and slowly killing the populace. An alien princess contacts the earth with an offer of a cure; but they need to travel to her. The Japanese battleship Yamato (Adm. Yamamoto's flagship, in WW2) is raised from the ocean floor and outfitted as a starship, to take a crew of volunteers to iscandar, to bring back the cure. They must fight their way through the aliens, there and back. It mostly involved space battles, without mecha; but, the series would influence the later shows which formed the basis of Robotech (Super Dimensional Fortress Macross, Super Dimensional Cavalry Southern Cross, Galactic Climber Mospeada). The American Star Blazers mostly just changed the names of characters and the ship was called the Argo. otherwise, they didn't alter that much.



Prior to that? Well, if you were lucky, you had Astro-Boy, Gigantor, or 8-Man, in syndication.

Gigantor, Mighty Morphin Power Rangers, Voltron, Astro Boy, and Iron Giant ... are some of the robots that I'm familiar of.

I also loved Voltes V and Daimos.

The series "Big O" from the 2000's was a great ode to the old Japanese big robot series of the 70's.

Just robots?

Robotech tops the list for me. Then there's Tranzor Z, Voltron (Lions and Vehicle), Transformers, Challenge of the Go-Bots, Gundam Wing, Patlabor, Neon Genesis Evangelion, Big O, Escaflowne, Hades Project Zeorymer, Robotix, all of the Macross sequels series. 

Then there's the forgotten and overlooked gem of Mighty Orbots:

I'm not really into anime as a genre, but I'm huge fan of old school mecha anime. Tops for me is Macross, which most people remember from Robotech, but it's actually a much bigger franchise that has been consistently releasing material since the original series aired. As a child of the 80s, I definitely watched lots of Transformers, GoBots, and Voltron (lion Voltron was better, but I still enjoyed vehicle Voltron and never understood the hate). Also enjoyed Mazinger/Tranzor Z and Mobile Suit Gundam, but never really got into the rest of the respective franchises.

I remember the Mighty Orbots from Saturday morning cartoons. And while not quite giant robots, there were all those cool high-tech vehicle based cartoons from the 80s that I enjoyed, like Jayce and the Wheeled Warriors and M.A.S.K.

Man, those were fun times. The 80s were a great time to be a kid.

Now that's my childhood!

I know Astro-Boy was the earliest, but I didn't see it until after I'd seen 8th Man and Gigantor. I probably saw Frankenstein Jr. but don't remember it. I've never seen a single episode of any of the other series mentioned so far in this thread.