I love any of the 6v6 battle episodes, especially Ash vs Paul, but I have to say my all-time favourite episode is definitely Camping It Up from the Sinnoh saga. I found Dawn and Grimer to be such an amazing pairing and I loved every single moment of the episode, as well as the rivalry between Ash & Angie and the extremely well personalitied partners they were given. (Shychu was adorable <3) This whole mini-arc of episodes was amazing and they're all amongst my favourites, but this particular episode is top due to this scene:
Though I most certainly haven't seen all of them, my favourite would have to be the one in which Ash's Charizard takes on Blaine's Magmar. That's probably one of the most epic battles in the anime, and being that Charizard is one of the most epic Pokémon certainly contributes to that. It's also the turning point in Charizard's respect toward Ash.
My favorite episode was also the one where Ash faces off against Blaine in Cinnabar Island. Pikachu can't defeat Magmar, but Ash finally learns to work together with his Charizard to come out on top. The part where Charizard spun Magmar and they showed an image of him circling the Earth in the background, for the seismic toss attack, was extremely exciting to me when I was a kid. Still brings back great memories.
I can't forget; I was also very choked up by the episode where Ash released his Pidgeot, moreso than with Butterfree, because Pidgeot was with him much longer and was one of his most powerful Pokemon. Can anyone fill me in on if he ever went back for him? He said he would, or so I remember. I tried to keep up with the newer episodes maybe 5-6 years ago but I couldn't get into it. I'm still concerned for the fate of the old characters/Pokemon though, lol.
I got some favorites. One is Gotta Catch Ya Later. Although it marks as the last second-to the last episode of Master Quest, it have this mixed emotions.. part of the nostalgic feeling when I was watching it the second time back then.
The episode 20 "The Ghost of Maiden's Speak" has always been my favourite episode. I also really liked the episodes where Sabrina appears. Actually the 1st season have many good episodes, however I don't remember any other episodes from more recent seasons that left their marks on me.
My favorite is Pikachu's goodbye...I couldn't help myself, it was the one of two episodes that made my cry. I consider this episode the queen of all pokemon episodes ever made. The display of the bond between Ash and Pikachu couldn't have been described in a better way.
The second wonderful episode is the famous Gotta catch ya later. I cried like about 10 minutes continuously. I just couldn't bear the end of the original series and original team. There is no substitution for that.
My all time favorite episodes are the Battle between Ash and May at the end of the Frontier saga when they split the rebbon.
And the episode at the end of Johto when Ash,Misty and Brock go their seperate ways.
My favorite episodes would be both "Numero Uno Articuno" and "The Symbol Life", the episode when Ash and his Charizard battles against Factory Head Noland. It was the first time that I get to see Articuno actually battle that's not in the games. It was also an interesting match up. Charizard Vs. Articuno...it looked like an epic battle!
The one when ash has to go get a ghost pokemon to fight sabrina and he becomes a ghost, either that or the one with the ninja gym leader, or the one when they are in the sunken ship, or the one when they are underground with the ancient pokemon.
'Bye bye butterfree' and 'charizards great ambition' were my favs includeing the first episode.'Bye bye butterfree' was the saddest episode ever and 'pallet party panic' when Ash releases his pigeot was sad too.