My list is pretty narrow. I like lots of people; anything with good harmonies and good lyrics is going to blow me away. I love songs as sung by Mick Moloney and Tommy Sands and lots of others. Most of my favorite sounds, though, are from the 50s- people like the Louvin Brothers, Reno & Smiley, Hank Williams, Kitty Wells, Carl Smith...
My favorite genre for years has been Southern Gospel, including that sung by Elvis Presley. I still sing it a lot and have taught it to some, although it doesn't seem to come easy for northerners! I tend to think the reason is that they haven't caught on that if you're going to sing something, no matter what the subject matter, you *have* to sing it as though every word were true. (Who was it that said that if you can fake sincerity, you've got it made?)
I suspect that is where the concept of soul comes in.