The Ikenobo School is the oldest ikebana school of today. It is also one of the biggest, both in Japan and internationally. I visited the Ikenobo headquarters and their ikebana museum in Kyoto a year ago and had a great time. You'll find my journal from the visit in this blog post. Watching this video introduction to ikebana brought up some good memories of generous hospitality and a fascinating history.
Ikebana artist Toshiro Kawase also appears in this video with a couple of examples of creative use of containers for ikebana. Toshiro Kawase is well known also outside of Japan. You might have seen his book Inspired Flower Arrangements that introduced him to an English speaking audience.