I'm in the burbs right now, and am looking at moving back to the city. There are still tons of apartments and townhomes for under 600 a room if you can stand roommates. They aren't gonna be in Rittenhouse square, but they aren't too far out either.

My gf lives in an older building 2 blocks from Rittenhouse, and her rent increased by about 1.5% this year. Philadelphia is still very affordable if you don't insist on new construction.