^for solo i'll recomend you
Lee Seok Hoon (well, only one minialbum as solist, but it's so amazing u need to listen to it, mainly ballads)
Kangta (pop&ballad)
Minwoo (urban sound)
Rain(urban/pop/allthestylesever)
Andy (pop! His second album, Single man, was one of the best last year!!
Lee Seung Gi (pop/Ballad)
Outsider (best raper ever)
Taegoon (aw, i miss him, just 3 minialbums, but it was amazing!urban/dance-y)
those are my recomendations XD all have AMAZING voices
(and most of them are really really sexy lol)