I've got some of the Telarc series myself, and bought the whole set for my dad a few years ago. They are superb, and mostly live up to the sonic glories of that label too, so seem the most apropriate recommendatiom in a hifi sense. I recall some had tiny cuts to fit them onto a 80 minute disc, but only a fanatic would be bothered, I suspect.
I've an old Mikado on cassette with the DC on Decca, and the actual singing is probably even better. I subsequently got several DC LPs which I've not played for a while.
Agree with Ashley that the Savoy Operas are worth seeing live, even by an amatuer group. Great fun. I once taught myself to sing "I am the very model of a modern Major General" just to see that it was possible to sing that fast. It is!