Consider some double doors or a garage door in at least one wall.
No matter how big you make it, at some point the shop will not be big enough for some project. I put double doors in one end of my shop and it lets me expand out the doors at times. Also, I can line up tools that require a lot of linear space, like the jointer, table saw, and planer and just open the doors for longer stock to feed through. The double doors are very handy when I am bringing in big stuff like plywood sheets, and when I need more ventilationlike when I am putting finish or paint on something.
If I could, I would have double doors at both ends, but one end is against my house foundation.
BTW, if you can look into back issues of Fine Woodworking magazine, through the years they have had several articles on shop design. There was a good one last fall on a small shop design. Some ideas work and some don't for each situation of course, but they are a good resource.
Have fun.
Walt