Phil West started it, so here's my own Top 10 List of Singers (defined as "...those that are immediately compelling, distinctive, built for fascination."), offered alphabetically:

Christina Aguilera
Louis Armstrong
Maya Azucena
Celia Cruz
Al Green
Sananda Maitreya (aka Terence Trent D'Arby)
Pink
Prince
Tupac Shakur
Uncle Kracker

What?