What exercise is best?

I'm at 200 pounds, 17 years old, and 5'6- clearly overweight+fat (obese even?) What sort of exercise would be beneficial to getting back to the normal boundaries? Tennis?

Any exercise you like, enjoy, and might even love doing! For me the best exercise is running....because I love to do it. For others it is walking, swimming, biking, and yes, tennis!!

You won't stick with something you don't like...try a variety of things and find what you can't wait to get to do again.

Honestly, the best exercise is whichever one(s) you'll actually do. There are people who love treadmills, but they bore me to death. There are those who love Zumba, but I've got no rhythm and horrible arthritis in my knees, so I can't do it.

Fine something you like - and even better, find someone who will do it with you - and just keep going! 

Going to go with the crowd.  The best exercise is the one you enjoy.  Doesn't matter if it is Zumba, Pole Dancing or nice long walks.  Reason is that if you enjoy it you will do it!  I recommend you try as many different things as possible to find what you like.  You will like different things for different reasons.  The act of running I do not like, except early mornings when I get to see the sunrise, but finishing a race regardless of distance is something I love.