If you've never heard the Public Enemy (which is important and one of their best songs but not the type of thing I wanna listen to very often), that also means you've never seen "Do The Right Thing", which you should try to rectify ASAP.
Sam Cooke is ####in great- maybe my favorite soul singer after Curtis Mayfield and really the artist who, along with Ray Charles, established soul singing by fusing the phrasings common to R&B and gospel. And Sam technically had a killer set of pipes which "Change Is Gonna Come" really exploits. It's also a key -and early- civil rights anthem.
"Robyn"'s also not ringing any bells for me but I suspect that it might be a 1-hit wonder situation (i.e. know the song but don't know the name).