Ken, since you said "tenor", and complete operas(which are very long and sometimes turn off new listeners)of course have a mixture of voices, I'll interpret this as singing(but not complete operas)from the world of opera or operetta with emphasis on the tenor voice.
Here's a nice collection of songs by the "three tenors"(Carreras, Domingo, Pavarotti); I really like Domingo's
Viennese operetta collection ; the greatest American opera is Gershwin's Porgy and Bess and
this is a very well-sung collection of excerpts.
