Freddie Mercury
Probably one of the best singing voices ever - his voice had a four-octave range. Not unusual for top opera singers - which may explain his love for opera.

Another huge influence, though apart from These are the Days of Our Lives (almost his own requiem), I preferred his earlier work in general.

All time favourites:
Bohemian Rhapsody, Killer Queen and the last song he wrote before he died, These are the Days of Our Lives.