It changes constantly. I’ll have one favorite for a while, then another.
When I lived in the Pacific Northwest, especially the early years, my favorite was the Steller’s Jay. They are colorful, but not gaudy; I watched them problem-solving at a puzzle feeder I put up for them; and they are not shy, but show themselves out in the open, often looking down from the tops of the tall conifers.
I’m a big fan of Tropicbirds because they remind me of the warm, bright places I prefer to be. They hunt fish at sea like terns, but then I also have seen them flying below the canopy in forest or with a canyon wall as a backdrop. That striking pattern of black-and-white, with the tail streamer, really draws the eye. I think if I had to pick an overall favorite, Tropicbirds would be the winners.