Of those listed, I guess Superboy and the Legion because that's when I was introduced to the Legion and I was really taken with them. The Adventure Comics I'd pick up at conventions or read in reprints were really fun too. But Legion is one of precious few DC properties that I've never taken a strong liking to so, honestly, my favorite is not a run; it's two short arcs:
1. World's Finest issue(s) introducing Composite Superman where the Legion were pretty much just statues, and
2. The Lightning Saga that ran through Meltzer's criminally underrated JLA and Johns' JSA.
I know that most DC fans have a ton of love for The Great Darkness Saga and maybe I would too if I'd read it when it came out or shortly after. By the time I was persuaded to check it out though, the writing already felt too dated for me to enjoy. As nostalgic I am about comics from my youth, I wouldn't be reading them as a middle-aged person if it weren't for the writing having become more sophisticated over time. As such, I can't really enjoy a superhero comic that's more than 20 years old or so.