Fearow by far; It was always on my team in Gen. 1 (except for Yellow playthroughs) and I feel guilty now that I replaced it with a Clefable in FireRed. I should train one up in White or Black, just for nostalgia purposes...
Hoothoot and Noctowl. Great designs, they learn Psychic-type moves and have nice defenses for these kind of early birds. Hypnosis is also useful when you catch Pokemon as well. And not to mention Noctowl is available pretty early on in HG/SS if you are lucky with Headbutt and find an underleveled one. XD
I was always fond of Pidgey and its family, and since I did grow up with these Pokemon it is perhaps one of my more favourite flying types. Hoothoot/Noctowl would come as a close second as I did always like their design).
The Starly line for me, as yes, it is the only one I have trained out of them all, but even in design, it looks the best, in my opinion. A much stronger build to it than the others, and an awesome second and third evolution design in particular.
Also, I like its movepool, and cry.
I only recently decided that I liked the Fearow line, and I can't claim to have tried it out (when I decided I wanted an alternate early game flyer I picket the Zubat line) but its something I'd like to try. It certainly looks suitably impressive and intimidating.
My favorite is definitely taillow, though pidove is a close second. Swellow is such a striking design, and it works well in battle, which just makes it really useful on a team. I always try to catch one when I play gen III.