very much depends on my mood, but right now would say, in no particular order, chris cornell, eddie vedder, paul rodgers, freddie mercury, david coverdale, billie holliday, barbra streisand, gladys knight, maria callas, glen hansard, bon scott, elvis presley, kerry ellis - all of whom move me with voice, performance or both
I think it all depends on the song.
I think that Karen Carpenter was the most amazing fremale vocalist that I have ever heard, but there are tunes that I would question that she could actually pull off!!
There are so many wonderful singers. The ones that please me the most have the least disciplined voices and tend to sound a bit more chaotic - so you're never sure how a new song might pan out. For me Randy Crawford does that best:
Here's an example of a collaboration she did with Steve Hackett, if it doesn't blow your socks off you have a heart of stone!!