I didn't get vanity plates until we moved out here, but we were not very creative. "GO R U" on the car honors our Rutgers fandom, while "AMYDOUG" on our Ford Ranger is just our names.
The thing is, they are not terribly expensive out here, and actually there is a plethora of different plates to choose from. In the end, I stayed with standard plates, just the custom letters. I briefly thought of getting a U of A plate with the "GO R U" lettering, but it is much easier to stick with what you have. Plus, last I looked, the UofA plates were not very attractive.