hmm...picking your favorite fish is like picking your favorite child...
i would have to go with my male blue, keeper of the peace, protector of the weak, defender of all that is good and just. He's the most peaceful fish in my tank and he has broken up a lot of fights just by his mere presence.
I would describe his temperament as that of a retired former heavyweight champion of the world. he's still very intimidating, but in all reality he couldn't hurt a fry.
He used to be real active and playful, and he had the most beautiful coloring, but with age, the energy and colors have both faded.
I got him at my trusted LFS, and he's 2 years old, which is about 50-60 in gourami years.
i like all my fish though, each has it's own quirks.