We have our new friend, Zac, to thank for the identification. He'd seen them in a nearby field the previous day, and did the research to confirm the i.d. I admit, I did a lot of Googling last night, and initially was beginning to question that it really was a Long Eared Owl, because the habitat described on the various websites just didn't square with where we saw this bird. In the end, I decided it couldn't be anything else, and the "X" of white feathers on the face, just barely visible on the image below, did the trick.
UPDATE 2/3/09: Heard from Steve Bodio, a man with much knOWLedge on the subject. He says, with about as much certainty as possible, that the above pictured bird is a SHORT Eared Owl. So there you have it. Good thing I hadn't checked anything off on my Life List yet.