I like barn swallows and bald eagles for much the same reason. I could watch both species fly all day long. I love the swiftness and agility of the swallows and the effortless soaring of eagles. I wanted to be able to fly like both when I was a kid.
Here in Texas, my favorites are scissor-tailed flycatchers, and cardinals just because they are pretty. I also love Bewicks wrens because they are such bossy, nosy little birds and because they have such a huge song coming from their tiny bodies. I also love that they nest anywhere and everywhere, in planters, in birdhouses, in helmets hanging in the garage.
Two of my all time favorites are chickedees and ravens. I could watch ravens all day. They are clever, and social and so good at problem solving. When we were at Yellowstone, there was a raven and a zip cooler in the back of a pickup. I told my kids to watch, and told them the raven would have the cooler open in five minutes. I think it only took about 30 seconds. The raven walked along the edge of the pickup bed, hopped onto the cooler and opened the zipper. I think his lunch that day was grapes and a ham sandwich.