I caught on to the J = "hook" theme at the intersection of DMAJOR (11D: Key of Pachelbel's Canon) and RINGINGOFFTHE[HOOK] (18A: Getting tons of calls), and the rest of the theme answers went quickly after that. I didn't notice until reviewing the puzzle, though, that all the black squares form Js - or hooks. Cute.
There's lots to like in this puzzle. First of all, there's a great new clue for my favorite bit of crosswordese - EEL - 21A: Fish whose name is a calculator number turned upside down. I don't actually know that it's really new, but it's new to me.
I spent a lot of time in the SW and SE today. ABJECT (47D: The absolute worst) and SALVOS (48D: 21-gun salutes, e.g.) are both excellent, but they took me a very long time to see. And on the other side, XYZ (62D: History's ____ Affair) was totally unknown to me, and I'm very sorry that I didn't see TRIX (61A: Colorful corn balls). I was flailing, not sure whether 58D: Little Caesar in "Little Caesar" was RoCO or RICO, and not sure at all about the aforementioned XYZ. Oh well.
I like the theme, and I like the extra touch of making so many Js out of the black squares. Let's give the whole thing a thumbs up.