I already have a J.D. - that’s a Doctorate… or so they say.
Add to it a Masters in Divinity
Er, “Doctor of Medicine” is not a Ph.D. There is such thing as an MD-Ph.D program, but most MDs are not Ph.D’s.
Masters in Heian-period Japanese literature , PhD in Geochemistry, specifically in paleoclimate analyses.
I’ve already got a Master’s in Information Science. But were I to get additional degrees, they’d be:
Master of Urban Planning - there’s just something about how cities work, from the money side to the development side that’s fascinating to me.
For a PhD, probably Anthropology. That’s another fascination of mine.
Seeing as I am too old to do much productive work with either one of the degrees, I’m just going to go for something a bit off. Give me a PhD in Ancient Languages (Etruscan a focus) and a Masters in International Affairs.
I’ve already got a PhD in Statistics (not so humble brag ;))
To assist me in my work it would probably best to get a PhD in molecular biology with an specialty in immunology.
As for the masters, I was thinking either psychology or economics. I really enjoyed the psych courses I took as an undergrad, but I’m interested in economics (even though I know next to nothing about it) and it might make a useful compliment to my statistics.
But I might go instead with philosophy. It’s another subject that I have some interest in, but while I might be willing to read up on psychology or economics on my own I doubt I would have the stamina to do all of the reading required to get a full knowledge of philosophy. So having it implanted in my brain is the only way that going to happen.
If you’re interested in reading up on economics I recommend Basic Economics by Thomas Sowell
Believe it or not there is a PhD in medicine. With thesis and all that. I have two PhD final exams in medicine. In both cases they were studying drug protocols in HIV positive people. For instance one of them showed that starting anti-retrovirals as soon as the person tested HIV positive, even before showing any symptoms of AIDS was an excellent idea for a number of reasons.
Now for the OP. Well I don’t have an MSc in math, but that would waste since I would learn nothing there. A PhD in linguistics come to mind immediately. For a master’s, may anthropology would be very insteresting.
I already have a PhD, so I would go with that. As for a new masters, I think I’d like something like math.
Masters in Library & Info, PhD in Museology.
Masters in Library Science, PhD in History.
M.D. for the doctorate. For the masters, probably neuroscience. Affective neuroscience I would guess.
I already have my master in psychology. I want the PhD in either music performance (trumpet) or writing. I am a fair writer and I was an OK horn but -------- I always wanted to be really good and well versed in at least the technical aspects of either.
Law would have been first choice, but as I age (and get to know more about medicine than I ever wanted to know), I lean toward medicine - specifically Hematology with a slant towards Oncology.
Just Hemo would take a few lifetimes, and the interaction with “cancers” is slightly more interesting than with the brain.
A master’s degree in psychology and $5 will get you a Subway sandwich.
Seriously though, for some people I know it does get them a pay raise, but I think any master’s will suffice. Normally it is either something you get on the way to a PhD, something given to someone who fails to get a PhD (for those programs where the first one doesn’t apply), or something ultra-clinical, but still requires additional internships and licensing. Mine doesn’t get me anything special.
I knew of the MA/PhD programs described above, but this is a pure research program then?
My purpose was to be able to do things as a volunteer and through church that I wouldn’t have been able to do (or do as well) without the degree. Yeah - most folks go to school to become richer or get a better/easier job. I am not quite one of them. 
Psychology or psychiatry, which I’m actually seriously considering getting.
A PhD based on an imaginary thesis entitled “The value of honorary and bought degrees in modern society”.
My biggest interests are Physics and Philosphy (in a broadly-defined way) so I first thought of those in some order.
Then I remembered that I am a self-taught but active and passionate musician, so getting a download of theory might be a cool mindblower.
But I am not sure. I haven’t picked up theory along the way and really value what I find by digging in myself. This would likely offend a deaf person, if so, sorry, but there’s a bit of Children of a Lesser God going on: I like being theory-deaf in some ways and see it as viable in its way.
Something to ponder.
Either this degree (Interdisciplinary PhD in Cognitive Science), which I’ve wanted for a while, with a Masters in theoretical mathematics.
Or masters in Architecture & doctorate in Urban Planning.
But that’s today. Tomorrow, I’ll probably want a different combination.