Scary how many responses are about stations that effectively no longer exist--that is, that haven't been big players in 20-30-40 years. In THAT category I'll vote for Altoona's 1290/WFBG, Harrisburg's 1230/WKBO & Waynesboro's 1130/WEEO--all top-flight Top 40 stations. (Today WFBG is news/talk, KBO is Christian, and WEEO got bulldozed 15 years ago). And, yes, the old 910/WSBA & 590/WARM were truly great radio stations 35-to-40 years ago. If Philly & the Steel City were part of this, 560/WFIL & 1410/KQV would get BIG votes, too. Oh, yeah, and 1020/KDKA.
Today--out in the woods? Chambersburg's 95.1/WIKZ, State College's 95.3/3WZ, Williamsport's 102.7/WKSB, and Altoona's 98.1/WFGY are all outstanding smaller market radio operations. The Froggy brand kicks booty in Johnstown & Meadville, too. On the AM side, Lewistown's 670/WIEZ does excellent full-service radio (and, man, that signal goes forever). Reading's 850/WEEU is also solid. Sunbury's 94.1/WQKX dominates the Central Susquehanna Valley. And way up in the woods, Du Bois' Country station Q102 sounds very good.