I think the general consensus is that stretching is good no matter what the sport, or non sport. There's a series of stretches for bike riders. It was given to me by a physical therapist but I end up doing just a few kids of stretches. Since I ride in the early morning before work, its important because I don't spend time (half hour) getting acclimated (wake up time).
The muscles that I stretch the most are the hamstrings. Standing up and leaning against one end as a support for my back, I would raise my leg and rest it on the opposite side. Hopefully the foot is about the height of my head or higher. I do this to each leg a few times with each time getting progressively easier and looser. I would hold this stretch position knowing its uncomfortable but not to the point of exteme pain.
For my quads, I would do a squat and hold the down position till I feel the quads strain. Then I would try to do the splits with both legs outstretched to the right and left. Obviously, I cannot do a full split but the movement does help.