Yeah, you can't get good cream cheese outside of Philly, which is a shame, because you can't get a decent bagel outside of New York City.
Are you looking for hole-in-the-wall restaurants or bars? I used to frequent a place at 13th and Pine (walkable from South Street) called "Dirty Franks" but it went from being an uber-hip place with the most beautiful women ANYWHERE to being kind of a hangout for fratboys.
If you want to stay on or near South Street, there's a Thai place called "My Thai" which is excellent, and super-cheap. Avoid anything with "Brasserie" in the title. Also, swing by the Bourse building, stop in the lobby of the Ritz at the Bourse movie theatre, and take one of their playbills. Flip through it and note the advertisements in it for restaurants. Avoid these at all costs.
Almost all of them are owned by the same corporation, and they're all the result of what you'd get if IBM anally raped George Perrier and then took a shit on Bobby Flay's corpse.
Oh, if you like spending two month's salary on a single evening of hedonism, then you must check out Deux Chiminees (not sure I'm spelling it right) which is the best meal you can get in Philly, and the best-kept secret on the East Coast (it is almost always possible to get a table there even on short notice, as it is QUALITY but I guess not TRENDY).
I really hate Philly society. The whole town is second class, second rate. But really, it's the *people* which inspire my ire. They're too hip for even themselves.
I don't even really notice how hateful everyone is here until I go somewhere else and see how people can be nice to each other.