This is one of the questions I get asked the most.
My short, quick, TL;DR... answer is always the same: get the camera you enjoy shooting with the most.
Keep reading if you want to hear me out as I go deeper into what I think you should consider when choosing a new camera.
The long and probably unsatisfying answer
You see, I firmly believe that gear matters - a lot!. But it's not about the megapixels, the sharpness of the lenses or the pedigree of the camera that I'm talking about, but the relationship between photographer and the device used to capture light.
If your camera is inspiring you, pushing you, challenging you, or simply put, if you have fun shooting with it, then you've made the right choice.
The point I'm trying to make here is don't waste your time with pointless debates like "digital or film", "35mm or medium format", "square or 6x4.5", "canon or nikon". Start with what you like to shoot.
My case: the three factors
From here, I'll use my case as an example that you might be able to apply to yourself.
There are three factors that define who I am as a photographer / artist and the tool I need to achieve what I want.
I got started in photography taking snapshots of my trips and adventures. A waterfall here, a person hiking in the snow, some foggy trees over there, a mountain--things easily shareable and likable that kept me hooked for a long time.
It was after a few years that I started to see myself becoming more and more artistic.
I didn't want to capture the world as it was anymore. I wanted to show it in the way I was seeing it - or rather, the way I wanted to see it). Monochrome was the perfect medium to do so, and I switched to black and white.
I also started to make square images. I could talk about this for pages and I will, eventually. For now, let's say that it helped me in my "mission" to show my images the way I imagined them.
Lastly, my images are made in a wide variety of places but most of them involve the great outdoors. Sometimes that means short walks from the car and other times that means hours carrying camera gear gaining thousands of feet while climbing a mountain. The size and the weight of the camera are important.
Size and weight
I like big cameras (and I can't lie), but they come with a tradeoff. The size and weight of your gear will limit the places you can go to. Unless you are in really great shape, bringing an 8x10 large format camera on a backpacking trip to the Enchanments would be a very hard and demanding thing to do - I couldn't even carry my medium format camera!
I'd like to add that even though it is not part of my "big three", the ease and speed I can get my camera set up is important as well. I don't usually photograph action or even wildlife, but weather is a big component of my photography and I want to be able to capture rapid-changing clouds and what not.
All this means that large format and some of the gigantic 6x7 medium format cameras are out.
Black and white
I can take black and white images with any camera, but film is able to capture monochrome scenes in a way digital can't, in my opinion. The way it renders the mid-gray tones is something I could never achieve with digital. I know there are some cameras with digital monochrome sensors, but they are very expensive and I'm not entirely sure their rendition is as good as film's.
Film also means that the process of making an image becomes more a craft: from loading the film to developing to scanning, I do everything myself. I loved that and still do.
Digital is out.
I was faced with my last big decision - 35mm or medium format.
But this choice turned out to be the easiest: square images were a medium format speciality (I know there are some 35mm cameras that shoot square but the negatives they produce are too small).
How I chose a medium format film camera
At the time I was looking for my new adventure companion, I owned a Rolleiflex. For those who don't know, this is a TLR medium format camera that shoots square, so it had almost everything I needed. But I didn't like shooting with it, and it didn't inspire me.
I started looking at SLRs, where a Hasselblad was the obvious way to go. But it was also very pricey and I never pulled the trigger.
Then I found them. Bronica made some pretty good cameras in the 80s and 90s, the SQ series. As you can imagine, they are 6x6 square format cameras.
The rest is history: I got one and it was love at first sight. Since then I've shot hundreds of rolls of 120 film and I don't see this love story ending any time soon. This camera inspires me and pushes me to get better, every time.
Despite its many flaws, I'm convinced it's the perfect camera for me. I seriously can't think of anything I'd add to it (besides a place to leave the dark slide when shooting). I hope I can shoot with it for many years to come and that I'll be able to acquire another one when the time comes that it finally breaks.
One or multiple cameras
All this doesn't mean you should own just one camera. I own several (including digital ones) and I try to use them all even though the Bronica is my main camera and the one I grab every time.
So, which one should I buy?
Forget about what others say (including me); take the time to think about the type of photography you want to make, and then look for the camera that will get you there.
And enjoy the ride!
If you have any questions after reading this, please go ahead and contact me.