My personal preference when going with one color plus white is to have a range of that color that blends well together, as if you were looking at a batik fabric and could get a sense of color depth when looking at the overall garden. I haven't grown them, but I really love those pictures of Cherry Meidiland and Rainbow Sorbet that Zuzu suggested. Unless you're going with a more formal symmetrical garden look, maybe you could consider adding something along these lines in a few places for added interest? I guess I'm thinking like a quilter here...
I also think some occasional pops of other colors such as purple or blue would be fantastic. Or even orange if you want a little more bounce. And you can still do minimalist -- although I betcha over time you'll manage to fill it! We all do!!!
Edit: I also love Betty Boop (wouldn't you know):
Rose (Rosa 'Betty Boop')
