Moonheart has a fairy tale aspect to it, but is contemporary (although it was written in the 1980's, bear in mind.) It shows what de Lint does best -- blending Celtic fairy myth with Native American myth and modern dwellers just trying to make their way in the world but sometimes seeing the edges of something else. It is the novel that boosted de Lint in the field and spawned many imitators. There are four other books de Lint did that are connected to Moonheart that form sort of a series -- Ascian in Rose, Westlin Wind, Ghostwood, and Spiritwalk.

Into the Green came later and is not one of de Lint's novels about Ottawa or his imaginary Canadian city Newford, the sort he's most known for. It's one of his more epic high fantasy stories about the world of the fey. So it's a little different, but if you're coming from alternate world fantasy, it might be a good transition book. And it apparently has its own soundtrack, so there you go. I haven't read that one, but I haven't heard anything particularly negative about it. His short story collections, like Moonlight and Vines, aren't a bad way to sample him either and see if you like the sort of things he does.

I also liked Memory and Dream, which is a Newford novel, the first one. It's a love story in good part, so some may not be interested, but it has some great material using art, mirrors, landscape, etc., that features de Lint's use of interconnectivity.

Ones of his that have gotten award nominations:

World Fantasy Award Winner, collection, British Fantasy Society nominee, collection: Moonlight and Vines
World Fantasy nominee: The Little Country
World Fantasy nominee, collection: Spiritwalk
World Fantasy nominee, collection: Dreams Underfoot
World Fantasy nominee, collection: The Ivory and the Horn
British Fantasy Society, World Fantasy, Mythopoeic Fantasy nominee: Trader
British Fantasy Society, Mythopoeic Fantasy Award, World Fantasy nominee: Someplace to Be Flying
Mythopoeic Fantasy Award nominee: Moonheart
Nebula Best Novel nominee, Mythopoeic Fantasy Award nominee: Forests of the Heart
World Fantasy nominee: The Onion Girl
World Fantasy nominee, collection: Waifs and Strays

Charles de Lint is one of the names I bring up regularly when people start acting like contemporary fantasy is some new thing because they finally noticed all the pictures of pretty females. He's a major bestseller internationally and a giant in the field. But if you don't like music stuff, he may not be for you.