One of my favorite rides (haven't done it since last summer, though) is a big loop from my home in Ridley Park, up 252 through Ardmore, out to Valley Forge and through the park, then down the Schuylkill Trail into Center City, then home (the last leg is also my daily commuting route). It's a "metric century."
The Trail is fun because I don't normally ride on paths, so it's interesting to do some riding where there are more bikes and skaters and joggers and no cars. It's slower and more dangerous, but fun, and the scenery is nicer.
My office mate commutes to CC daily from Manayunk on a Trek hybrid I sold him. From the tales he tells, I'm just as glad there aren't any bike paths on my commute.
I'm sure you'll find the perfect bike, and this is a good place to come to for advice.