Not sure if anyone did this already, but doing it anyway
Vote and discuss.
As for my choice, its the 1990's. To make a long reason short, the characters for the most part were likable, the story lines were fun, the villains were really bad, and the mecha battles were at their best.
Well, I've got favorites from the 80s, 90s, and 2000s.
I guess if I was to pick a favorite, then I would pretty much just go by which decade had the most seasons I liked. For me, that would be the 90s. I enjoyed 8/10 of it's seasons (Jet, Dai, Kaku, Oh, Car, Mega, Ginga, and GoGoFive).
I loved 5/10 from the 80s. The second half basically (Change, Flash, Mask, Live, and Turbo). And I loved 7/10 of the seasons from the 2000s (Time, Gao, Aba, Deka, Magi, Bouken, and Geki).
Definitely '80s, especially since these titles set new standards that are being followed by today's Super Sentai titles:
Taiyo Sentai Sun Vulcan (1981) - The first and only Super Sentai trio. Later titles such as Choujuu Sentai Liveman, Ninpuu Sentai Hurricaneger, Bakuryuu Sentai Abaranger, Jyuken Sentai Gekiranger and Engine Sentai Go-onger followed the "core trio" concept. Voted #4 best Showa era Super Sentai title in a recent 35th anniversary special.
Kagaku Sentai Dynaman (1983) - The first Super Sentai to use Spandex outfits.
Choudenshi Bioman (1984) - The first Super Sentai to have two female members and a robot ally. Voted #3 best Showa era Super Sentai title.
Choushinsei Flashman (1986) - The first Super Sentai to have a secondary giant robot.
Hikari Sentai Maskman (1987) - The first Super Sentai to have a combining robot out of five vehicles. Also the first to introduce a sixth member (unofficially).
Choujuu Sentai Liveman (1988) - The first Super Sentai to have a female blue warrior. First use of an animal-based mecha. First show to have two giant robots combine into a more powerful robot. Voted #2 best Showa era Super Sentai title.