Oh my...what have I gotten myself into!

[MommyBird]

Another vote for avoiding the big-box stores. Walmart, Target and K Mart.
Go to a real bike store. Actually, go to several real bike stores. For a starter bike, you will pay twice as much as a big-box level bike but you will be getting 10 times the bike and eliminate the headaches.

As stated above, replacement parts are not readily available for the cheaper bikes. They rattle and ride rough. Components vibrate out of place constantly. My husband spent hours trying to adjust our boys' friends sub-standard bikes. Our boys' LBS bikes, on the other hand, required minimal work.

The local bike shop will be a wealth of information and source of on-going customer service. You will have a place to go for adjustments, maintenance and all those accessories that you will just have to have.

The hybrid is also a great suggestion. Comfortable, stable, versatile, not too heavy, peppy and it has a full range of gears.
Cruisers are cute but they are heavy, lack gears and are not very stable.

http://bicycling.about.com/od/howtoride/a/hybrids.htm

[tiva]

You've got some great bike shops in Knoxville! Visit a few. Cedar Bluff has the Trek FX series, which are well worth checking out for the kind of uses you're thinking about. Make sure you try out a bike or two that costs a bit more than you want to spend, as well as a bike or two that costs less than you want to spend. It will give you a good feel for the trade-offs you might want to make!

[PamNY]

Hey, I did a lot of biking in Knoxville. Of course, that was in the 1960s when I was in college at UT.

You definitely want a hybrid and you want low gears -- a beach cruiser or comfort bike will make it too hard to explore those beautiful hills. I live in NYC (mostly flat) and I'm glad for my granny gears.

I did luck out on a used Trek -- bought it from a bike rental place. I agree with the caveats about Craigslist, though it's worth checking.

Good luck!