What do you want to be able to see on the other end. If you're shooting 200yrds at prairie dogs, you need a different scope than you'd need to shoot deer at 200yrds, and equally different still than a scope you'd need for shooting IPSC torso style targets at 200yrds.
Following along that, what is your price range?
Here's something you might be interested in reading:
HNI Scopes & Sights Forum: 5 Best and Worst scopes by Price Range for 2015