Who are the most underappreciated artists in music?

This doesn't necessarily mean a band you like that isn't famous. I'm talking more about artists that you think are great, but are almost always left out of musical discussions, and are somewhat unfairly cast aside or written off by many listeners, despite whatever influence or importance they have. For me, I've always felt like Kate Bush and Genesis are two artists like this. (Years ago I would've included Rush, but in recent years they've finally got the respect they've deserved.) Kate Bush is my favorite female artists of all-time, but for some reason no one in the States knows who she is. She's royalty in England, but in America, it's all about Madonna. And Genesis is always written off because of their poppier, more accessible 80's work, but very few people know that their 70's work is an entirely different thing, and that they made a few masterpieces with Peter Gabriel on vocals, not Phil Collins.