I am a fish freak. I have multiple aquariums, keep adding more, my sister works at a fish store (which I got her hooked on), and I am a moderator on a very popular fish forum on the 'net (and probably the only one with an adult/naughty section hahahahaha).
I have so many favorite fish but I tend to love the ones with a lot of personality, and the smart ones that can learn tricks (yes, fish can learn tricks) -- large freshwater eels, goldfish, puffers, bettas/Siamese fighting fish, oscars, etc.
But I also love cool water/subtropical fish like danios (like your glofish!), white cloud mountain minnows, and so on.
I also love bottom feeders of so many types, like corydoras, otos, plecos, and various other catfish.
I adopt a lot of my fish, such as deformed fish that need good homes. I have a severely deformed Corydoras weitzmani and a crowntail betta who was born with no caudal fin. So I guess you could say one of my favorite kinds of fish are the special needs ones. XD