One of mine would be "(If Loving You Is Wrong) I Don't Want To Be Right" by Barbara Mandrell. It was a #3 R&B hit for Luther Ingram in the early 70s. She recorded it in the late 70s and it was the second #1 from her Moods album (following "Sleeping Single In A Double Bed"). I think it's probably the best vocal she ever did, especially for an official single release. It didn't sound particularly 'country,' but had a nice easy R&B vibe as did much of her music from the 70s. The song was her biggest cross-over pop hit, reaching #31 Billboard and #26 Cashbox.
[video=youtube;9H24K8-xaPk]https://www.youtube.com/watch?v=9H24K8-xaPk[/video]