While I haven't had the chance to come across such nice vistas like Krutj, and the Liberty Bell has never interested me enough to go see it; there is one thing I can recommend: beer. The Philadelphia area has a very vibrant microbrewing community, and you can find great pubs, bars and restaurants in Philly that serve great locally brewed beer. I think Pennsylvania beer will give any state a good run for its money.
Other than that... well, there's the Philly murals, and the ever popular Rocky statue (*sigh*), and as already mentioned, Amish country is a nice and unusual thing to see.
Like some people have mentioned, Philadelphia is unique. Obsessed with their sports; their sense of humor is weird and awesome, just like Always Sunny in Philadelphia... its an awesome place.
__________________
|