For casual bar with a non college atmosphere, come to Gene's. Great prices, decent selection and friendly service. A downside for me was smoking is allowed, but that may be all around Pittsburgh, so I'm not quite sure. Gene's is unpretentious and small but bring your friends, relax, have a tall beer or mixed drink and just have fun. There's a dart board for those of you that need more to do. A random plus for us was the juke box. News of Whitney Houston's death only brought us to all sing loudly with the juke box.
Dive-y, great prices and a great bartender. How do you go wrong?