I'm a nominal fan of James Brown, having been introduced to his music in college in the late-80's. I played in a cover band that did "Papa's Got A Brand New Bag" and "Sex Machine", though we were clearly stiff, white, and not particularly funky. (We tried...) That said, one thing that struck me about James Brown's music were the rhythmic off-beats and the hypnotic nature of his songs. It was good stuff musically, and to my mind, in the same way that Frank Sinatra isn't really talked about for his musical ability, ditto goes for James Brown. The image and the public persona overshadowed his innovation, though it shouldn't. He was a grounbreaking songwriter, using drums and horns in ways that nobody had ever used them before. Legend has it that if he had inspiration for his music, even in the middle of the night, he'd call his entire band into the studio on the spot to record. Sometimes he'd do the same while on the road. He'd stop the bus in some town on the way to a gig, find a studio in that town, and lay it down.
I never saw James Brown. I wish I had, and when I had the chance a few years back (he was playing at B.B. King's Club in NYC), the ticket price was pretty stiff ($80), so I passed. In the end, it was my loss.