Ive lived in the city my whole life, and i also run an entertainment business on the side, so im always out and about.
As far as places to eat, you gotta do Pats or Jims, i think they are a toss up.
If you want a cool sports bar, that has good seafood, hit up Chicky and Petes, its a good scene, good drinks, and the foods wild.
As far as places to go out:
Rittenhouse Square: Upscale, older crowd, great restaurants, good drinks. Probably best sit down and eat seafood is there, Devon.
Old City: Great clubs, bars, lounges. You can ask anyone where that area is, but to keep it simple the radius is 2nd and 3rd, and Market and Chestnut.
If you want to hit up a few hot clubs, i would sugggest:
Denim- Rittenhouse Square
Red Sky- Old City
Comments that say a city like philly sucks, its just ignorant... If your with the right people, you will have a crazy time. And the right girls here, do it up...