Originally Posted by Dahon.Steve
Get a copy of "Bicycle Gearing" by Dick Marr. It more technical but it will make sense after a second reading.
The Left hand gears are incredibly important. I use the left hand (front Derailuer) each time I ride and will no longer purchase a bicycle without the tripple. The reason being, dropping to the tripple allows me to reach a low gear very fast without having to drop two or three gears on my right hand (Rear Derailuer). Once I get to the top of the hill, I simply click the left hand back to the middle chain ring and I'm finished.
But that's really important because you're going down hills really fast. The OP might be in a flat area. I have a two-gear front, and I live in flat NYC; I only shift my rear, because I just don't have the opportunities to upshift on big downhills. If I were on a big hilly ride, I'm sure I'd use the left (front) shifters/derailer more.