Ok, let's keep this train rollin'. First thing to state is that the vocalists I defined as 'classic' all had their hey-day in the 60s or 70s. Some endured and still put out great stuff after that; some coasted on their success; some faded into oblivion. But, most of their best output came in the 60s or 70s. With that out of the way....
Another tier-1 showdown, more progressive this time though. Steve Walsh of Kansas vs Dennis DeYoung of Styx. For my money, DeYoung is one of my favorite vocalists. Smooth, powerful and what a range.