Love Natalie Haynes (new book coming out about Jason and Medea in a couple of weeks and seeing her live in Oxford - fan girl excited!), Madeleine Miller, Pat Barker and Jennifer Saint. Always sad not to see Claire North's name on these lists, if talking about Greek myth retelling, as her Penelope trilogy, The Songs of Odysseus, is superb.
There's also nothing like reading the actual The Iliad and The Odyssey - Emily Watson's two translations are totally gripping. Margaret Atwood's Penelopiad is a quick, slightly depressing, read. I found Colm Toibin's The House of Names a bit chilly, but it's an intelligent read.
Greek Myths by Charlotte Higgins gives a really good over arcing view of many Greek myths. Ted Hughes' Tales from Ovid is as fantastic as you'd expect from a poet of his ability. The Marriage of Cadmus and Harmony by Roberto Calasso is more about the philosophy of myth but excellent.
Worth listening to the myth episodes of Natalie Haynes Stands Up for the Classics on BBC Sounds.
I absolutely hate all Stephen Fry's versions.
Mary Stewart's Arthurian books still hold up: start with The Crystal Cave followed by The Hollow Hills, The Last Enchantment and The Wicked Day.
Can't think of anything else at the moment, but if it comes to me, I'll be back.