I'm just going to interpret this as "favorite" voices of all-time.
Male:
1. Michael Jackson. A prodigy and a musical genius.
2. Kevin Max. Christian singer and poet. Was a part of dc Talk. Does his own solo stuff now. If you haven't heard him sing, please do me a favor and listen and comment... I just think he's incredible. Here he is doing a cover of Queen's "Save Me":
http://www.youtube.com/watch?v=GVGsluyCGNU&feature=related
3. Freddie Mercury. What a range.
4. Don Henley. Love the rough, raspy quality of his voice. Makes him stand out.
5. Ray Charles. I can just feel the raw emotion seeping out of his soul when he sings.
Female:
1. Stevie Nicks. Most unique female voice.
2. Ann Wilson. Such power.
3. Mariah Carey. Back before she became a pop diva, she was a serious singer with loads of talent.