I only just noticed this...!
I'm gonna go with Jimmy Cliff, this is probably based mostly on the fact that my Mum loved him so I was bought up on him more than any other reggae artist (Desmond Dekker, Johnny Nash and Prince Buster were a few of the others I grew up with).
Probably most well known for 'You can get it if you really want' and his covers of 'Wild World' and 'I can see clearly now'.
My favourite album is probably 'Wonderful World, Beautiful People', the title track and 'Viet nam' being the best (in my opinion). According to the Lord Wikipedia, Bob Dylan said 'Viet nam' was the best protest song he'd ever heard.He was also in 'The Harder they come', unsurprisingly featuring pretty heavily in the soundtrack. To be honest, I didn't think a lot of the film, but meh.
In his early 60s now and still going for it... Top bloke.
There's probably, actually, definately better reggae artists out there but as I said, Jimmy Cliff sticks out as my favourite.
YouTube - Jimmy Cliff - Vietnam