Originally Posted by MRT2

OK, found a couple of articles that explain it. It all starts with cadence, or rhythm. As this article says, it isn't about speed, but about your legs. So gears exist to facilitate cadence, which allows for longer rides without exhausting your legs.
http://www.bicyclepaper.com/articles...-Gears-Are-For

Here is an article on the terminology of bike gears.http://beta.active.com/cycling/artic...-to-bike-gears And another article on the subject. In general, look for a road bike with a triple chainring, or compact double.
http://beta.active.com/cycling/Artic...e-Gears?page=2