Hi Ron!
Hmmm
As a (poor) student of philosophy, I know that comparative discussions tend to be meaningless unless they're based upon clear definitions. So what, I have to ask, constitutes 'greatness'? If it's an ability to sing every note exactly as it appears in the score, then perhaps you ought to consider a 'technical' singer, such as
Peter Pears, as a candidate for the word's greatest tenor.
If, on the other hand, 'personal interpretation' is more important than simple 'technical ability' then
John McCormack certainly becomes a candidate.
The 'majority opinion' seems to favour
Placido Domingo:
http://www.bbc.co.uk/pressoffice/bbcworldwide/ worldwidestories/pressreleases/2008/03_march/m usic_magazine_domingo.shtml
However, Luciano Pavarotti's opinion was that the title 'the maestro' belonged solely to
Giuseppe di Stefano.
Chris