A Blank Canvas Staring at Me

I have a large, 24x48, gessoed black, blank canvas sitting on my easel upstairs. It has been yelling at me for days to go and put something on it. My mind has considered many possibilities, but the first thing that begs an answer is, horizontal or vertical? This may not seem like a big deal to some, but for an artist there are plenty of questions...
First, weighing what is commercially viable vs. what you want to do is a huge issue. There has to be a balance here or all of us would be painting small, large headed children with doe eyes in raggedly clothing...but I digress. A vertical painting in such a large size is difficult for someone to place in their home/office/workplace or wherever the painting eventually will end up. This can be a killer for a sale. I have found that when people think about buying a painting, more often than not, they already have a place in mind for it to hang. What will sell, what the public wants, will have to be balanced with what I want to paint, and what I want to say. Sometimes these things are at odds with one another and at the end of the day, I have to still pay the rent.
Because this canvas is fairly large, but by no means huge, I also have to think about storage and transport. Yes, it will fit in my station wagon, but some people have little, tiny cars and they simply can't get a large canvas home. Also, this larger canvas takes more time, more paint and will cost more money. More everything. I would love to paint HUGE things, but it's not practical, and so this 24x48 is big enough to satisfy me for "large" but not so big that I have to borrow a truck to transport it.
I have a plant in my yard that I quickly stuck in the ground in Oct. after we sold my mother's house. It is a peony from my grandmother's house in Woodstock. Now it has beautiful, pink flowers. I am thinking about painting big, fat, peonies the size of my face on this canvas. I also think that I will do it in a vertical format. Too bad if it will be hard to hang. It will be interesting to see what I do as I think that I will carry the image around in my head for a few hours while I go for a walk. I will paint it in a variety of ways long before I actually put paint to canvas.