Last year I moved into a really great apartment with a rooftop patio but I didn't really do anything with my outdoor space until I had a chance to do a lot of research and plan the space accordingly. First thing I decided on were Tillandsia or Air Plants because they're really interesting to look at, easy to grow, and can grow in almost anything, whether they are indoors or outdoors.
They can grow with or without soil. However since they're going outside, my first attempt will be in soil in these rather beautiful sustainable pots from France by a company called Art Terre. They're made out of 100% Pévétex.
They come in a variety of colors and sizes for both indoor and outdoor use and they're sold through a company called Bouf based in the UK. They're reasonably priced even with the exchange and shipping and I think they're fairly comparable in price to some of the pots I've seen.