Coolest looking legendary (gen 1&2)
I vote zapdos
Answers
Weedle.
(well, I WANT it to be a legendary - as in a legend we tell future Pokémon Go players and have them go "Sheesh, they never had that in the game. Drink your prune juice, gramps, and take your medicine. Weedles in Pokémon Go? What, did Santa Claus put them there?" (Censor) you, Weedle. (Censor) you.)
My thoughts:
Gen 1:
Arcanine's designated as the "legendary Pokémon" (pipjay already mentioned this guy). My favorite Pokémon ever, though to make this fair for the "real" legendaries I'll leave Arcanine out.
All the birds look awesome but they're not top contenders here.
Mew is perhaps the cutest legendary Pokémon there is (imo).
Mewtwo is okay.
Gen 2:
Raikou and Suicune look nice, but...
Entei is my favorite of the beasts by far. It's a lion and lions are cool. The third Pokémon movie might have something to do with it as well. ;)
Celebi is okay.
Lugia is one of my favorite legendaries. It looks awesome!
I never thought much of Ho-Oh's looks. Sure, it's big and colorful and all that but it didn't impress me (>90% of my Pokémon background is the TCG). BUT Ho-Oh's 3D-model in PoGO looks just... outrageously fabulous. It's looks alone are a good enough reason for me to power up one!
So my personal winners are:
Mew, Entei, Lugia and Ho-Oh.
Final notes:
Entei doesn't look as good in PoGO as in the movie.
Ho-Oh looked okay in the TCG cards but in PoGO it might even be the best looking legendary released thus far.