There are different types of road bikes for different cycling purposes. The good people at RovobikeReviews.com have produced this useful infographic explaining four types of road bikes.
They are:
1) Road Race (also known as Road Competitive and Road Aggressive)
2) Road Relax (also known as Road Endurance or Natural Position
3) Road Fitness (also known as Upright Geometry or Upright Position)
4) Triathlon / Time Trial (TT)
There are different body positions to suit each bikes, such as 2 o’clock, 12 o’clock, 1 o’clock and so on.

Read more about these four bikes on RovobikeReviews.com