How do you find a good bicycle/bike shop?

[Banshee Fay]

I know that I should have looked into this in the spring, but better late then never. I want to get a bicycle for exercise. I don't want a stationary bike. Atleast not yet. How do I find a good bike? I know I could find one at a sport authority or walmart, but I want to get it from a store the specializes in bikes. How do I find a good store? I figure it's not going to be cheap. The couple times I've gone thru friends and friends of friends for a bike, it's never became a done deal. I could try craigslist, but I'm not really comfortable forking over 200 bucks to a stranger for a random used bike, when I could invest more money, and get a new bike from someone who has many bikes available, and will be able to find the best bike for what I need. I know it's picky, but my problem is, one person I was borrowing a bike from, I couldn't use because I was too short for it. I don't want to travel all across chicago trying to find a bike that will work with my short legs. I hope that makes sense.

Thanks for any help!
As for the bike I am looking for, I just need one for exercise around the suburbs. I don't understand the difference between the kinds of bikes, but I just need one that I can rely on not to break in my pothole ridden hometown. If you have any suggestions for a type or brand of bike I should look into, please feel free to give me any tips!