Frank Lovejoy is a favorite radio voice of mine as well, and his acting on Nightbeat was outstanding.

I can always spot the voices of William Conrad, Raymond Burr and Gerald Mohr on OTR shows even when uncredited. There's no mistaking their voices for anyone else's, even when they're doing regional or foreign accents. These three guys are among my favorites. I also like Marvin Miller's voice.

Paul Frees was among the most versatile voice actors of all, not always easy to recognize, either. He could do a killer Orson Welles impersonation. Welles, btw, is not a favorite voice of mine, as I find his acting hammy, his voice too "God-like" to be convincing as anyone but Orson Welles playing God playing Orson Welles. The few Suspense episodes he did are all lousy in my opinion, with Welles throwing every one of them off due to his over-acting. I actually prefer the TV Twilight Zone version of The Hitch-Hiker to the radio version originally done by Welles.

Agnes Moorehead was indeed the queen of OTR as far as I'm concerned. The absolute best.