As many said, Staraptor and Talonflame seem to be the kings of the roost (pun intended). Both have their pros and cons, but are generally the best of the main birds.
Staraptor: Has Intimidate standard, Close Combat to pummel Rock and Steel types, can learn Steel Wing via TM, when it has Reckless, Brave Bird/Double-Edge hits like a warhead, highest attack, good speed, cool design
Talonflame: Flame Body is very useful, Gale Wings grants +1 Priority to Flying moves, fastest of the birds, learns Steel Wing naturally to deal with its major headache: Rock, gains Fire-typing after evolving, Flare Blitz/Brave Bird make it a one Mon wrecking crew, cool design
So it's a tough choice between those two. And I love both either way, as they are awesome birds. But I may have to go with Talonflame just because its typing and wider moves give it a slight edge over Staraptor (but it's still right up there).