Cobb's Creek is now closed, still waiting for the renovation. A few publics close to downtown worth checking out:
Jeffersonville GC - Lots of recent work by Tyler Rae and Ron Pritchard to bring back more Ross features, it's very enjoyable over rolling terrain.
LuLu: Semi-private, another Ross that features lots of bold mounding and a great short par 3 volcano green.
Glen Mills - regarded as one of the better public courses in the area, a Bobby Weed design in a very serene setting that moves between meadows and woods. I have not played it this year yet know it has seen a drop in conditioning since last year, am hoping that changes since it's a great course. Should still be in pretty good condition regardless.
Riverwinds: Just across the river in NJ and set next to the DE River, wind is usually a factor and it's a pretty good round even if not. Low profile and a good deal of variety, I always enjoy myself more than I expect here.
JC Melrose - Have not played here in years, but an interesting history with Mackenzie and Maxwell. The course was altered from road building decades ago but the greens are still a lot of fun and I enjoy a lot of the holes. No idea how it has been playing recently though.
Further away from Philadelphia proper worth playing depending on location:
Wyncote - a heathland style wide open layout that maintains interest with its undulating and twisting fairways with a fair amount of blind shots and a few forces carries. Has a nice cadence to it.
Pilgrim's Oak - A Hurdzan/Frye that's best characterized a farmland links; it's pretty far from downtown but if staying south of the city, may be worth checking out.
White Clay Creek. An Arthur Hills design with lots of forced carries and a much more modern tournament tone to it, in Newark, DE. Lots of raised greens that vary in size and, did I mention the forced carries? Still, I find myself always coming back here. I think I like the greens more than I realize.