Ok, so my list may seem an unlikely place for these next artists to end up -- indeed despite our general preferences in this draft I am surprised they are still available. But I've always had the utmost respect for what they can do and they scratch an itch I've had for vocal harmonies on my island in a major way:
Boyz II Men
Now R&B is clearly not my music. In fact in its modern incarnation as a bad form of synthesized urban pop singing about how I am going to sex you baby, I find much of it vaguely pathetic. But Boyz II Men were something else, featuring nearly perfect vocal harmonies, singing many songs nearly acappella, which is something I love and am glad to have on the island, and turning out some seriously beautiful songs that worked no matter if you were an R&B guy, a rocker, or whatever.
In the early 2000s they lost one of their four original members to health problems (the bass voice) but continued on in diminished form spedning much of the decade doing covers of everything from old motown to modern pop rock and country songs. Some of the covers are quite good, and as with Joe Cocker, Joan Jett, Social D etc. in this sort of draft I consider good covers to be a major bonus point actually, bringing more variety of msuic to my island.