I bought the Booker's, like I said, and it was a real success! Amazing bourbon... we sipped it neat, the way my girlfriend's dad drinks most of his Scotch (unless he pours in a little water). Very strong and good. Thanks again for all of your help.
By the way, since I was at the Philly duty-free, I can update you all on what they had. It's a pretty expensive duty-free -- my double-carton of Marlboro Reds set me back almost $50. Whiskey was not much better. There was a bunch of Wild Turkey bottles, but no Kentucky Spirit or Rare Breed. The Booker's was $46 (so I guess I got a good deal) and the Baker's was $28.
Bottom line, it's better to look for specials at your liquor store than buy at the duty free if PHL is where your connecting flight leaves from.