Thanks again everyone for your advice/input on a road bike.

Here's a little update:

So far, I've put about 35 miles on the bike, and the rear derailleur started acting up (i.e., jumping between gears on the rear cassette). I took it into REI and they not only adjusted it for free, they showed me how to adjust it for future problems. AND this adjustment didn't even count as my "warranty tune-up!" I definitely recommend the service at REI.

After the little adjustment, things are going great!