I've done a bit of homework, looking through my bird identification books, and checking one or two books during my trek to several bookstores this afternoon.
I've reached the conclusion that what I saw last week was an immature red-tailed hawk. The Ferruginous Hawk doesn't live in the eastern US, and the rough-legged hawk's legs are feathered farther down than this bird's legs were.
There was a bird book by National Geographic that showed a picture of an immature red-tailed hawk in flight. The light morph of that (as opposed to the darker-feathered one that, from what I gather, lives out west) was the only one pale enough to really resemble the bird I saw.
Ya know what's REALLY aggravating? I *had* my camera with me. It was in my tote bag. I was just so taken aback by seeing a hawk right there in front of me, I forgot everything else. I wish the thought had crossed my mind that I could try and get a picture of the bird.
Oh, well. Maybe he lives near the building where I work. If he comes back, NEXT time I'll try to photograph him.