Synagogues and Restaurants. If you like Israeli style felafel type stuff, Mama's Vegetarian in center city Philadelphia is affordable, consistent and tasty. Take out or eat-in. Enjoy your visit.
DANF] I can vouch for the New Harmony Vegetarian Restaurant in Chinatown (downtown area). They are vegetarian, and they had a reliable hechsher as of about 4 years ago, last time I was there. I thought they were quite good.
The Swiss Haus Bakery in downtown Philly (I think it was around S 19 St.) was under International Kosher, as of about 4 years ago. I don't know what its status is now. But, if it's still kosher, some of their cupcakes were so good, I would specifically travel to Philadelphia just for them.
Downtown area has picked up quite a number of kosher places within the last few years. Otherwise, the kosher places tend to be clustered around Castor Ave. in NE Philly.
Kazi: I attended Mekor Habracha, which is not a kapoteh and shtreimel place, but is packed with young and nice people on Shabbat. For the less religious Beth Zion - Beth Israel may be a good option. The 1818 Market Street minyan was also a good choice for weekday mincha. I've heard good things of Mama's Vegetarian, even though they accept only cash. Hey Hummus is serving meat as well, it has an IKC hekhsher (please decide, whether you consider that reliable). It seemed to me that Hamifgash was closed, while Swiss Haus received again heksher under IKC. I found that Rittenhouse Market was selling quite many kosher products, including bread, dairy stuff and grape juice.