If you are going camping...23, 24 or 30. Its hard to go wrong with any of those sites. Close behind would be Deep Creek.
If you are looking at a day trip, my favorite is the Gorge section of the WPLP (but don't tell anybody......)
Tremont is close and the horseshoe is famous, but I haven't enjoyed either as much as the other places (of course I had my flyrod stepped on and broken by one of my fishing "buddies", so I only fished the first 1/3 of the 'shoe last year during the drought - Steve, I love repeating that story....)
"Even a fish wouldn't get into trouble if he kept his mouth shut."