Honestly, I can't say I know much of Richie Havens great body of work. I don't know why. But, what I do know, is, he was one of the most emotional and "human" voices I've ever heard.
My first real exposure to Richie was via Steve Hackett. As a huge Genesis fan, growing up, I also delved into all of the solo careers of the Genesis guys (Steve being the guitarist in the 70's era). Steve's 2nd album "Please Don't Touch" featured Richie on 2 songs. I was mesmorized by the song "How Can I?". A nice Hackett composition, but certainly not one I'd list in his Top 10. With all due respect to Steve, if he would have sung this song it would have been "ok". But, Richie brought this "simple" song to life, in a way that only very few singers can.
Selfishly, Richie is an artist I wanted to contact at some point in the future - simply to see if there was any chance he would grace one of my (our) songs with his voice. (I've become slightly spoiled with the guest artists that have graced our songs). A few years ago, there was another passing of a voice I hoped to contact down the road...Kelly Groucutt (bassist and great 'backing voice' of ELO). Granted, we're all mortal... but recordings are timeless and I often fall into the trap thinking these artists are immortal as well. Selfishly, I'm glad their recordings ARE timeless...their 'immortal gift' to us.
Steve Hackett summed up Richie's gifts beautifully on his website blog - much better than I could ever do: http://www.hackettsongs.com/blog/steve112.html