Rarely do I replay a song on vocals, but Widower is definitely one I come back to regularly. It's a challenge at times; the verses offer little to no breathing room (literally) which really tests how long you can hold notes for.
And then there's the awesome screaming section after the second verse... Everything slows down... And then for the last few seconds, it picks itself up, as if to say "Hang on a minute, mate, pay attention, we're not quite done yet!"
The atmosphere this song creates makes it fun to play on any instrument, but supplying these incredible vocals is an awesome experience.
Who'da thunk it? A metal song that's fun to sing?