Unless you are a serious body-builder, there is no real reason for you to isolate on one muscle group at a time while lifting weights. While there is nothing wrong with the bench press or chest press, they are examples of strength exercises that do a good job of isolating on the chest area and not much else.
If you are just a regular person looking for some added strength, push-ups are a far better option. Besides working the chest and arms, push-ups require trunk stability, involving back, gluts, and abdominal muscles. When you think about it, the muscles in your neck are also required to hold your head in a neutral position.
Of course, the biggest plus about push-ups is that you can do them anywhere anytime, without any special equipment.
Not that equipment isn't available. Pictured here is a push-up power rack (pushuppowerrack.com), allowing the user to vary width and angle of grip. You can also make them more difficult and recruit muscles differently by resting your feet on a bench or chair. To make push-ups easier, beginners can start with their knees resting on the floor rather than their feet.
Finally, because push-ups are more of a muscle endurance exercise than a pure, high intensity strength exercise, you are less prone to packing on too much upper body muscle weight, something runners and cyclists don't really need.
(c) Dave Elger, 2007 All rights reserved