With how popular some Gym Leaders are, you'd almost forget what kind of Gyms they actually run... or not. Some Gyms can be very memorable because of their puzzles, layout, Gym Leader or Trainers, etc. What's the Gym you remember the most fondly? Let's hear it >_> One Gym that'll always stick with me is the Cerulean City Gym in FRLG because of the sheer number of times it took me to finally beat Misty because I had chosen Charmander as my starter. It was painful because every time I'd challenge her she'd always be like "Oh, I haven't seen your face here before" or something along those lines it'd piss me off every time. One of the Gym Trainers also had rare Pokémon like Shellder and Horsea so that was cool and later on you could fish and surf there too. The highlight of my BW2 playthrough (possibly my favorite Pokémon game) was definitely the Nimbasa City Gym. The catwalk, the music, the reveal of the final stage and the fight were all so incredible I've never been more hyped for a battle than that fight against Elesa.
I think it might be Grant's gym that surprised me the most. I mean we could climb it, vertically. That was so amazing! I do hate the Relicanth in that gym. Ruiner of Wonderlocke's, like Grant... The one that I love the most for its design would be Norman's gym im OrAs. I love the traditional style even if it might be impractical to have wooden floors and a Slaking.
I don't have a specific gym in mind honestly, but I've got a soft spot for most of the Gen 2 Leaders. I think Morty's Gym was the coolest, followed by Clair's. Besides that I loved Elesa's Gym in both BW/BW2. Roller coaster was incredibly neat and the catwalk really set the scene for the battle.
I love Skyla's gym in Black 2 and White 2. The cannon at the end always gets a chuckle out of me. *enter cannon* Weeeeeee! SPLAT! *instant regret after sliding down wall*
I really liked Lt. Surges gym, it was just so sneaky and seemed so simple but was actually hard to get in order. Also the stories to be had at the gym made me like Surge a lot more, hyped me for his battle
Personally, I liked Drayden's/Iris's gym in Black and White the most. It felt intense being in his gym, as he was a dragon type gym, but his gym made it much much more cool and exciting to get to him.
Olympia is kind of forgettable as a gym leader in my opinion, but her gym is amazing. Starts off as a small little room and then bam, off goes the walls and ceiling and suddenly you're this vast space with floating paths and warps that loop around in a rounded circular kind of way. It gives the impression of strange disorientation without actually being disorienting or a pain in the ass to navigate in practice.
The right answer is obviously the Ice gym The coolest Gym to me, most likely, would be the Elesa's Gym in Unova.
My favorite gym is the Azalea Town gym in Johto. I like the idea of a gym inside a green house, and the web and lever puzzle was really fun. Bugsy is also my favorite gym leader just for his wonderful and slightly sassy attitude in the anime. I would love to see the Azalea Gym in full 3D in a future game/remake. I think it would look amazing. I also loved the ladybug shaped Hive Badge too.
Valerie's gym from X and Y will always be memorable to me. It looks like a huge doll house, and the teleporting is a big callback to Sabrina's gym.
I really like Norman's gym as it actually looks like a place where people would train. But my favourite has to be Wake's from D/P/P. There's something about pressing those buttons to raise the water levels that's just so gosh darn appealing to me.
Surge and Koga's Gyms were memorable for being infuriating the first time I played Fire Red. XD I always remember tate and Liza's Gym for being the only Double Battle Gym so far in the entire series. The spinny things were also fun.
Gen1 - Giovanni/Sabrina (tie) Gen2 - Whitney/Bugsy (tie) Gen3 - Norman Gen4 - Wake Gen5 - n/a (probably Skyla) Gen6 - Olympia