I swear Hayami Sho has one of the (if not the) sexiest voices ever in anime

I would stretch that to just plain anywhere. Hayami Shou is the reason I watched Trigun in the first place, because Yami and MoB made me a junkie. He does sound very different as Wolfwood, because he's being so OTT a fair bit of the time instead of all cultured and refined. Even with the Kansai, he's very recognisable when Wolfwood is being contemplative and serious.

I could just listen to that man's voice when I didn't have a clue what he was saying!