Putting it all Together
This site could go on and on about the physics of the bicycle. The most important points have already been covered though. What's next is to put all the covered points together to make sense of it all. The bicycle is an incredibly efficient machine. Nearly all the power put to the pedals goes to moving the bike and rider forward.
Unfortunately, there is no such thing as a perfect bicycle. For example, a very aerodynamic rider position will not allow the rider to produce as much power, and will also be very uncomfortable. Deep-rimmed wheels are aerodynamic, but they also have much more material at the outside edge, which means it requires more torque to get spinning, and so does not accelerate as fast. Very aerodynamic frames also tend to be much heavier.
A pack of racers asking for the most from their bikes in the final sprint to the finish.
Because of this, the people that are lucky enough to be paid to ride a bike use different bikes for different kinds of races. For races that involve lots of climbing at relatively low speeds, they will use a very light bike with very light wheels that accelerate well. For fast, flat races, riders will use a slightly heavier bike and wheels in exchange for better aerodynamics. And for time trials, where the rider is by himself and must cut the wind as best as possible, a time trial-specific bike will be used, which is the most aerodynamic bike you could use.
Superhero Lance Armstrong on his climbing specific bike.
American Tyler Hamilton on his time trial bike.