We always say "Zee Zee Top" - I think there's a sort of unspoken acceptance that they've earnt it. But you sometimes hear people say "Jay-Zed", normally as a bit of gentle mockery.

Am in Australia, we use 'zed' for the letter 'z'. but it's different for the band, as that's a proper name. You go with the pronunciation of the owner of the name.

I come from a "zed" country but we normally use the pronunciation of the people/creators.

So if I were reading the name "Jay-Z" for the first time and had never heard of him, I would think it was pronounced Jay-Zed or maybe Jays, but when I heard his name said by others I mentally adjusted it to Jay Zee.

Imagine if the whole alphabet was like zed instead of like zee:

a bed ced ded ed f ged h i j k l m n o ped q r s ted u ved w x y zed

I had ties to both Zee and Zed-speakers growing up, but in my experience, Zee and Zed can be used somewhat interchangeably, even across the pond. This might be in order to account for names (like Z Z Top and Jay Z), puns (such as La-Z for lazy) or even ease of pronounciation - when playing CSGO, I've heard Americans refer to the CZ-75 as Cee-Zed-Seventy-Five, because they found it weird to switch between the cee, zee and seven sounds, but I'm not sure how common this is.

Asking the real questions.

… and I hope to the gods it’s Jay-Zed

As a Canadian it really depends whether I say Zee or Zed. Looking online I was surprised to see that it has apparently been Zed in Canada for a long time, but I distinctly recall being raised on Zee until about the mid 2000s then everywhere in the curriculum it was Zed and I started hearing it more. Probably the biggest influence on whether I say Zee or Zed just depends on pop norms, and what sounds better.

Some examples:

• Zee Zee Top, obviously
• Jay Zee
• 350Zed and 370Zed (in reference to Nissan's sportscar models, this actually changed for me over time, for the longest time I would say 350Zee or 370Zee, but when referring to the model broadly, it's always Zee Cars, or for the classic model, it's Fairlady Zee. Fairlady Zed just sounds awful)
• Day-Zee (the movie and video game)
• Dragon Ball Zee (ALWAYS, Dragon Ball Zed would be madness, I've never even considered saying Zed here, perhaps because I encountered it more in my Zee prevalent childhood)
• Zed-DX (the Acura)
• BMW Zed4
• La-Zee-boy (the sofas, obviously, ruins the pun otherwise)
• Alfa Romeo SZed (another car, it seems any time it is separate letters or a series of letter making up a name it's virtually always Zed)
• ABC song, is always Zee for me, but I've heard others say Zed her often. To me it's weird because otherwise it doesn't rhyme with "next time won't you sing with me". Oddly if you asked me to say the alphabet backwards though, my first instinct would also be Zee.
• the phrase "from A to Zee"
• If you asked me what the last letter of the alphabet is, or to spell Zebra, I would say Zee, it seems when referring to the letter alone I pretty consistently use Zee
• I just asked my wife to spell Zebra and she said Zee though

At least the British and Americans are consistent, I don't even know what the heck I'm doing here!

Here in Australia where we also pronounced z as zed not zee, I've never heard anyone say zed zed top and it's always zee zee top. However, while I personally would too rarely find myself on a conversation about Jay-Z to be able to gather enough data to form a conclusion, I vaguely feel like I've people both say Jay-Zed and also Jay-Zee though I'm not quite sure.

I think the thing is, without being able to explain why, Zed Zed top just seems too obviously not the intended pronunciation that it's just a no brainer to interpret it as Zee knowing that they're American and American culture being so ubiquitous that everybody knows you guys say Zee. Jay Z theoretically should fall under the same rule but I think it's easy enough to say Jay Zed without it feeling weird and wrong that same people might opt for their familiar Z pronunciation over the source Z pronunciation, though I'd say it's not typical.

No

If it’s a company name or a band or something then I’ll say zee. But acronyms like ZFS are always zed.

I always wondered how do we pronounce the videogame "DayZ"? Is it like "daisies"?