i dont have a single favourite. i would never be able to choose!
i love plecos 'cause they're funny looking lol
i love loaches because they are so cute
cories also because they are cute
harlequins 'cause they are active
big american cichlids 'cause they are...well...BIG
tetras because they look great in schools
I've had limited experience with fish species-wise. Bettas are my favorites so far, but I can't help but love goldfish and Koi. Just too much of a hasstle to keep.
I voted Other for platy, but I could equally well have voted cory. Or female guppy-but there wasn't a specific box for that. Used to love my kuhlies too. (I'm no good at these poll situations).
But I think the platy has a lot going for it. Easy to keep, lots of pretty colours, inquisitive and sociable, right size for the sort of tank the family will let me keep...