A decent enough Monday. I was annoyed for a second at the theme, because I didn't see them all as blues songs, but then I re-read the revealer clue, 63A: What the artists of 16-, 27-, and 49-Across are doing (in reference to the last words of their hits)? (SINGINGTHEBLUES), and I realized that it was more about shades of blue than the blues, so, not bad after all. Only four answers are involved in the theme, but they're huge (2 15s and 2 13s), so it still adds up to a lot of theme squares.
Some nice non-theme long stuff in here, too. GETTYSBURG (29D: Locale for an 1863 address), AREWEALONE (2D: "Can anybody hear us?"), and the WOEISME (6D: "Alas!")/RUBITIN (9D: Gloat) pair. I don't know why I think of them as a pair, but I do. Both seven letters?
Some somewhat unusual stuff, especially for a Monday, like 17D: Nobel-winning author André (GIDE), and SENEGAL (44D: Dakar's land), and some all-too-normal stuff, like TSAR and ASEA. But overall I liked it just fine.