This map is about three years old now, but I doubt the information on it has changed much, so I thought it'd be interesting to examine the top five city and suburban ZIP codes by major metropolitan area (at least 1,000,000 population). I'll start with the metropolitan areas I know best:
Best ZIP codes in the city of Pittsburgh
1. 15217 (83rd percentile)
2. 15222 (75th percentile)
3. 15220 (70th percentile)*
4. 15232 (68th percentile)
T5. 15216 (61st percentile)*
T5. 15236 (61st percentile)
Best ZIP codes in the Pittsburgh suburbs
1. 15015 (97th percentile)
2. 15090 (97th percentile)
3. 15142 (96th percentile)
4. 15241 (96th percentile)
5. 15367 (95th percentile)
Best ZIP codes in the city of Atlanta
1. 30327 (99th percentile)*
2. 30305 (93rd percentile)
3. 30306 (92nd percentile)
4. 30319 (92nd percentile)*
5. 30326 (91st percentile)
Best ZIP codes in the Atlanta suburbs
1. 30327 (99th percentile)*
2. 30005 (97th percentile)
3. 30022 (95th percentile)
4. 30068 (95th percentile)
T5. 30024 (94th percentile)
T5. 30075 (94th percentile)
T5. 30097 (94th percentile)
*: Denotes a ZIP code located in both the city proper and the suburbs.
Feel free to add to the list if you choose to. I'll try to add some later when I get the chance.