Queen, of course!!
i wouldn't say they're the best ever but top 3, easy. "a night at the opera" is a ridiculously good album. i WILL say however the freddie mercury is my all-time favorite lead vocalist, though. god-like range, both in terms of hitting a wide variety of notes and being able to convey a wide variety of moods. we're lucky he wasn't brought up differently, or his might've been wasted in opera or something ;)