I think Red has a point here. There are many ways to define "talented". We all have our favorites, and an arguement could be made for any one of the singers mentioned. Sometimes a singer doesn't have to have perfect pitch or even a wonderful voice to be considered a "classic" singer. A certain voice just works with a certain kind of material. Singers like Bob Dylan, Johhny Cash or Neil Young would probably never make it if thier careers started today. It's all about the music that the voice is incorporated into. That's where songwriting comes in, and is so important. Lennon and McCartney may not have been the most utterly talented singers in the world, but thier music was written to perfectly match thier ranges and strengths.
Something like "best singer" is such a relative question that it's hard to pick a few without reverting to your own personal favorite music. There are singers out there that I like simply because of thier ability to harmonize. I've been in bands where I wasn't the featured singer, and I can tell you that spending the whole night belting out high harmonies can be more grueling than singing lead.
Anyway, these may not be the "best singers", but they're the voices that I've always liked and respected...
Steve Perry, Journey - Not only a killer range, but packed with emotion. On tunes like "Anyway You Want It" and "Mother, Father", he sounded like he was having sex while recording the vocal tracks.
Geoff Tate, Queensryche - another "raw talent" vote. Six octave range and all without screaming.
Rik Emmett, Triumph - Just like the sound of his voice, especially on his solo stuff.
Peter Gabriel - Again, there's something about his inflections, tone and timbre that does it for me.
Kevin Cronin, REO Speedwagon - Probably a surprise choice, but he's got one of those elusively high ranges. He sings naturally in a range that many reach falsetto for. It doesn't sound like it's up there until you try singing a few in a row.
Jon Anderson, Yes - THE voice of progressive rock. All in a five-foot package.
Steve Hogarth, Marillion - It's rare that I like the replacement singer in a band after the original has left. Marillion has left behind the early-Genesis-sounding epics and moved into some really ethereal territory. Steve is powerful from down low and unreachable up high.
Chad Kroeger, Nickelback - Raw power that's hard to sustain for more than one tune. On our set list, I have to put "How You Remind Me", "Someday" and "Too Bad" in three separate sets.
Tori Amos - Not the best female lead, but her angelic voice fits perfectly with her writing style.
Stevie Nicks (pre-Jack Daniels-cocaine-insanity) - Her best work was on the Buckingham/Nicks album. If you're only familiar with Stevie from Fleetwood Mac and '80's solo stuff, get a copy of Buckingham/Nicks. And speaking of...
Lindsey Buckingham, Fleetwood Mac, solo - Not awesomely talented, but I really dig the sound of the man's voice.
To avoid any future argument, I know I've left out a million classic singers. I don't claim this list to be "right", just my personal favorites.
