Why You Should Run
Okay, I'm clearly biased. Don't expect impartial advice here. However, there are lots of reasons why you should run.
Exercise is Good
It is a fact that a strong heart and strong lungs will make you more healthy and make you live longer (on average). If your heart is stronger, it pumps more blood per stroke. This means that your heart has to pump less to force the same amount of blood to flow. This means that your heart beats fewer times during any given time period. Since your heart has (approximately) some fixed number of times it will beat before it gives out, fewer beats means longer life.
Having strong muscles, like the kind you'd get from running, is a big health benefit. Not only will you look better, you'll feel more energetic and stronger. You won't get winded walking up two flights of stairs.
Exercise makes people happy. Hard to believe, but it's true. Exercise is a great outlet for relieving stress. After a hard day at work, going to the gym for a workout will make you forget all about your evil boss.
Why Run?
Running is a great form of aerobic exercise, and aerobic exercise is the type of exercise that improves your cardiovascular health -- meaning your heart and lungs.
Anyone can run. You don't have to take lessons or spend lots of time learning how to run -- everyone knows how to!
You don't need any special equipment. Beyond a pair of shoes and some running clothes, you don't need anything. Don't have a pool nearby? That's okay!
Running gets you into nature. One of the best things about running is that you can go for a run in the morning and find an animal staring at you, watching you pass by. You can be by yourself without distractions.