I have so many favourites! I'll give you best by category
Keep your smogon comparisons to yourselves, I'm not a competitive player, these are just Pokemon I like
Cuteness:
CHIMCHAR!
Chimchar was the first starter I really connected to. I loved that little fucker so much, and it was super rewarding to watch him grow into an Infernape.
Close second: Pachirisu
Anime Character:
Jessie's Wobbuffet
I don't know why they gave Meowth speech and not this guy; from the times he pipes up I bet he has some great jokes
Battle power:
Omg my Infernape. Or my Skarmory. Or my Infernape. Or my - you know what? Tie. I love the wall/tanking power of both these guys equally!
Design:
Luxray; his stats are weird for an electric type, but I love his design! I wish so much he was Electric/Dark. Coulda got more Physical moves that way, too.
Shiny Design: Umbreon
csn you tell I have a fondness for dark types?
Close Second: Mega Charizard X
Sentiment:
Totodile: my very first starter!
Other mentions include Belossom, Ninetails, Lugia, Growlithe/Arcanine, the Cyndaquil line, Staraptor, Fennekin, the Froakie line, Blaziken, Ponyta/Rapidash, piplup line, snorlax, cubone/Marowak, Espurr/Meowstic, klefki, Flabébé line, pidgeot, and Shuckle. DON'T FUCKLE WITH SHUCKLE.
I could probably go on