ive got a foldable pro fitness exercise bike from argos - around 90 quid. its great - can watch tv in the morning and get up a real sweat on it. tells you speed, distance, calories burnt and heart rate. has 8 resistance settings but i only use number 3 and 4 at the mo!
i think if i still lived with my parents in the country i would be tempted to get a mountain bike and ride through the woods, but as i live in a very flat city the exercise bike is fine!