I like to keep a low profile, and refuse to get a "vanity plate" for the following reasons:
1) You don't need to advertise to potential thieves
2) I like to "play" with with a modified car, and it's a lot easier for someone to remember & report a personalized plate, rather than a bunch of random numbers and letters.
Fly under the radar, and make ID more difficult in ticket happy [i.e.: revenue enhancement] states, which is now EVERY state in America!