Most of the original content on my permaculture site will feature photographs that I’ve taken in my garden, so I looked for themes that showcase photos. Responsive design is also important, which narrowed the choices down a bit. Beyond that, I prefer a clean, uncluttered look, and a white background.
Here are three that will work, at least as a starting point:
Oxygen has a featured content slider, which is a great way to show off photos, and lots of options for page setup.
Origin has minimalist look, also with a responsive design.
Foghorn caught my eye with its color background and posts in boxes with white backgrounds.