There are some songs that are perfect. The perfection comes in the performance. No one needs to cover it ever since we have copies of the original. I am willing to say some like I Will Always Love You has two perfect versions, Dolly Parton and Whitney Houston versions. On Americas Got Talent a singer just covered it, I would have Xed him in ten seconds.

Other songs Somewhere Over The Rainbow sorry Judy Garland version is perfect. The very definition of a song that never ever should be covered.

Respect by Aretha Franklin perfect no need to cover it.

With A Little Help by Joe Cocker no one can sing it better.

Gloria by Laura Brannigan oh god this is perfection to listen to. One of my fav all time songs.

Other songs?

I think maybe a cover sometimes feels like they are meddling in my memories.