Camden NJ is one of the only places where you can get AIDS just from looking at the welcome sign. Avoid
10th & Arch St will be your happy place. The Trocadero. Best metal club in the city. Its also in the heart of China town, some great places to eat around there and the hookers are willing to negotiate
You also have The Electric Factory a few blocks before and north, right off Callowhill street, can't remember if its 6th or 7th for the cross street.
The venue mentioned on South Street by ROFL is called the TLA (Theater of Living Arts). Some great metal shows there but the place sucks. Whole thing has a weird downward slope from the back to the stage and the sound is usually mud but still, its worth checking out. Also have Dobbs a couple blocks away from there right on South st. Local legend kinda pub/club and the Cheesesteak place is right there as well. Fantastic german pub couple block past there, Brauhaus Schmitz ... great selection of beer and the food is really good too. If you're walking around there be sure to explore about 1 block in either direction off of South onto any of the other streets (2nd - 10th), some really weird and cool shops, pubs, etc
UofA section is cool enough to walk through depending how high your tolerance is for kids acting dumber then they actually are for attention.
Old City has all of the historical stuff and you can cross any of the walkover bridges on Front St to check out Penn's Landing ... some cool restaurants and bars on that side of the highway.
If you're into the club thing, start learning Delaware Avenue and everything on it
If you're into the gay thing, start at 13th & Pine (The Gayborhood)
Do NOT walk around by yourself anywhere near the zoo
There are NO germans in germantown ... avoid
Some great things to check out a little outside the city area but close to where you'll be. ... awesome metal / rock club about 10 minutes south of the airport called Tom N Jerrys on MacDade Blvd and literally 5 minutes from TNJ is a place called Warehouse 24 ... lots of metal shows there as well, cool place, both of those are right off I-95
So yeah, center city area is cool, avoid north and west ... NE Philly is ok enough