Check out the link posted by tSara Yap. I would also say to take a look at Bay Harbor Islands. Home prices are high, but the condo market is great and many condos have great water views. Bay Habor has their own Police force, A rated elem. school and has a great community feel.
Crime can hit at anytime in any nieghbor , but since your here in north miami here is a link as to the crime stats in cities nationwide you'll find and click the neighborhood that you would like to search for.
If you need any assistance feel free to call me at 954-643-3403