I'm in your area, and know many of the shops you're visiting. They are all great places, and will treat you right no matter what you decide to do regarding a new bike.

You'll get lots of advice here on which specific bike is best for you. Look for the bike that fits your primary need the best. If 95% of your riding will be daily commuting, pick something that fits this requirement as best as possible. You'll be able to take that same bike around Cades Cove with NO problem. Many riders go up there at night during full moons and ride the loop, it's a blast! You'll also be able to take the same bike around the Green Ways when you want to get out for a good long day on the bike. Doesn't matter if it is a hybrid, "city" bike, cyclocross bike, touring bike, ect.

When you get comfortable on your bike and if you find yourself wanting to spend more time on longer road rides, consider another bike specific for that task down the road... no need to make compromises right now.

The most important "features" for a daily commuting bike are things others here have mentioned: ability to fit wider than normal tires, potential for a more "upright" riding position, eyelets that allow the use of fenders and racks, potential for built in lighting systems, simplified drivetrain for easy cleaning and maintenance, ect.

Will you be riding at night? Will you ride when it rains? Would you possibly consider an upright "city" bike with all these features built in, including a generator hub so you never have to worry about charging your batteries for lights?

The bottom line is that 5.5 miles is a nice comfortable commuting distance that can really be done on just about any bike. Pick one that will make your ride enjoyable, comfortable, and convenient.

Breezer makes nice "city bikes." Tennessee Valley Bikes near downtown is a dealer.

PM me if you want more info about local shops, suggestions on routes, ect.