Yeah, it's certainly unforgettable:
"PYUUN tondeku Tetsujin...NIJUU-HA-CHI-GO!"
I kid, I kid, I kid. I knew which one you meant; that one is a classic too.
@GWOtaku:
It's interesting that you mention the "most recent take was preoccupied with the WWII issues". The original manga, and the Japanese version of this version originally took place just shortly after the end of WWII. When Fred Ladd adapted this show as Gigantor, he changed the setting to "the future" (forget the exact year, though). For the 1980 version, the Japanese version takes place in the present day, and is a more "modern" interpretation of "the space age robot" (as the English song calls it). However, the English version of that made it out to look like a sequel in which the "Gigantor" we see is a "faster" and "stronger" version. Meanwhile the 2004 version returned to the original version of the story as Mitsuteru Yokoyama (the original author) envisioned it.
Incidentally, I first heard the Japanese theme song on You Tube. Fun fact: before the opening begins proper, there's actually a plug for the show's original sponsor ("GURIKO, GURIKO, GU-RI-KO!"; look up "Glico" on Google or Wikipedia). In all honesty though, I kinda like the Japanese theme song better...to the point where they should have adapted that one instead of creating the timpani-driven most people are familiar with (not that it's bad mind you, I'm just saying). The Japanese one is more "superheroic" sounding, and IMO fits the show somewhat better.
Anyhow, while I'm not in a real hurry to get this DVD, it's one I certainly would like to have.